Running it outside with everything attached.
Will have the flip in 15 min.

Guiding is good - below 1" RMS but even after tweaking I still have RA runaways every 1-3 minutes.
Those are just spikes which settle in 10-30 sec.
I guess it's OK but if someone knows how to get rid of them - please let me know.

For guiding I settled at:
Min/Max RA 120/12
Min/Max DEC 1000/12
0.5s guiding interval.
Internal guider.

Thanks!

The flip didn't go well.
It went under horizon.
When I parked after that - the position was off by 90dgrs in RA.
I guess, I had to have "simulate pier side" option enabled (without it the pier side was "unknown').
Next time I'll see if it helps.

Also, after the flip, the DEC guiding became worse (still good at around 1") but RA spikes disappeared.

Continuing talking to myself...
Tonight, I am having the second night out with the mount.
Same thing - guides smoothly at 0.6-1.0" RMS total and then every 1-3 min RA spikes.

Out of curiosity I installed a counterweight (2kg). Luckily, I had a proper shaft and a weight.
Guess what? No more RA spikes/runaways!

That's with my smallish AT72.

I wanted to lighten my travel bag with this mount but it's not going to happen, I am afraid....
Guiding is really great at 0.6-0.8" RMS total now.

Did you sort out the flip? Was it side of pier? I haven’t used mine with StellarMate/EKOS in a few months. Been using ASIAir and trying NINA. But previously had no issues with the meridian flip. I did have to set a 5° past meridian limit in the hand control, then set EKOS to flip at 3 minutes past meridian. That seemed to work for me. I’m anxious to get back to EKOS, as it’s still my favorite capture application. But we’ve had such a string of bad weather, it feels like it’s been a month or more without any opportunities to use it.

Yes. I don't know what happened the first time I tried the meridian flip...
The second time it worked fine.
Also when I enabled the "simulate the pier side" option it made matters worse. I keep it OFF.

The pier side is "undefined".

I don't use the hand controller at all.
I figured that it's only needed to be used once to push coordinates/date/time to the mount for a particular location.
If you travel to a different location/time then the HC needs to be connected again and synced with the mount.

So, my scope is in the default RST Park position (horizontal, facing west).
I connect to INDI/Ekos and there I have its Park position defined as facing NCP. So, I park it from Ekos and it goes to NCP.
In the end of a session I manually drive the mount back to horizontal position (with Ekos Mount Control).

I sometimes encounter problems where the mount travels the opposite direction of where it's been asked to go. For this reason, I home the mount every single time I boot it up. I've also seen where I might start it up, home it, and let it sit for a few hours, then issue a GOTO command and it doesn't know where it's pointing. So I have to home again, then reissue the command. I have no idea what causes this erratic behavior. I've also seen on occasion that if the mount moves from west to east, and you send it back west again, sometimes it thinks the shortest route is to continue east until it gets back to the point you sent it to. This makes the cables wrap around the mount. I also don't know why it does this.

But typically homing before using the mount in anyway keeps all these scenarios from happening.

Yes, I think it's a good idea to have the HC handy in case the mount gets confused.
I intend to use this mount mostly for travelling to dark sites - I will need it anyway to update the location.

I found that leaving the mound in the "standard" parking position - scope pointing at NCP is pretty safe in terms of the backdrive.
So, in the end of a session I don't bother anymore driving it to RST's default home position (horizontal facing West).
Just reporting.

Waiting for the good weather to return and the Moon to go away to play more.

Update...

-- good people here on INDI forum recently fixed the driver (thanks!). Location push is now behaves as it should. It's only available on beta channel at the moment.
-- I went out to a remote dark location with RST-135 and RC6.
-- had the hand controller connected and GPS signal acquired.
-- launched KStars/Ekos (KStars was set to Mount updates KStars). Location got updated nicely.
-- all was good but I didn't realize that I had to change my parking position (pointing to NCP) - it was still using my usual location/longitude.
This caused some issues since it was parking in a crooked way. Once I copied/pasted the new longitude to the parking position everything became OK.

-- new thing I didn't know before - if you click Home Mount in INDI control panel RST-135/Main Control this will home the mount as the hand controller would (horizontal facing West)

I was thrilled to find this.  I did read the thread (tome?) on CloudyNights, but it doesn't seem like many there are on the INDI platform (I'm running StellarMate 1.6.1 on a Pi 4 with 8 GB).  Plus, I've forgotten much of what I've read since it's long, I'm getting old, and the thread is kind of all over the place.

I'm trying to set up a Borg 90FL with Starizona Apex feeding a QHY268C on an RST-135 (f/3.6, 325 mm when all is said and done).  I'm seeing the spikes you mentioned and look forward to trying the counterweight (my system is pretty light).  Also, my RMS numbers are horrid (~6 or worse), and I'm guessing that is a mix of operator error (I'm new to guiding... didn't really need it much in the past at this short focal length) and not enough light reaching the sensor of my ASI290MM Mini (I'm using an OAG, and the mirror is quite small—the guider keeps losing the stars and starting over).

I also have a 30mm f/4 guide scope, and I'll give that a try with your guide numbers tonight, skies willing.  What I was wondering is whether you have updated numbers?  I figured I might as well start with the latest-and-greatest.

Finally, I'm also seeing the unpredictable mount behavior mentioned above.  On a couple of occasions, it's lead to cord wrap—one time bending the USB socket of the mount (I'm learning this is a weak spot on the Rainbow Astro design but am learning to work around that).  I reached out to both the vendor and manufacturer, but neither have been responsive—a little disappointing and scary when you're trying to work through issues on a $4000 USD mount.  Anyway, I digress, but it does both me that the support has been lacking.

Here's hoping that you're still monitoring this thread!

Thanks,
Greg

I think most of these problems have been eliminated through firmware and driver updates. You’ll learn to religiously home the mount after boot, or connection to software so that the mount knows it’s starting point. After that it will goto pretty good. A single plate solve using the align/sync will get you centered on an object. Really most default settings, even for guiding will be pretty straight forward. You will want to use .5 second guide exposures so the mount can correct quickly for the large periodic error that it has. Anything slower than .5 seconds and it can’t correct fast enough to keep up with the error rate, and you’ll drift off target and back again over a full cycle of the strain wave gear.

PHD2 can also be used with KStars/EKOS, and a full run of the strain wave gear using guiding assistant (4 minutes 20 seconds) will give you good settings to use for the mount. Ignore any backlash recommendation. Then the only other thing worth looking into is just how good you can get polar alignment.

Last, make sure you have the latest firmware.