Glad to hear you're making progress. I seem to recall I had been using internal guiding without problems, but like you, I also stopped using guiding for a variety of reasons.

#1 - using a long local length telescope and an OAG it's still quite hard to find stars for every target, which due to the way EKOS handles errors means that a sequence is abandoned when guiding can't be started (rather than going unguided and capturing the best data it can) WHICH BRINGS ME TO #2
#2 - with mounts like the Paramount ME (and the APs, 10Microns, Planewaves etc) it's generally speaking easier to go without, perhaps with the occasional re-target part way through a sequence just to get back on target

So I've really stopped caring.

Having said that you remind me that I recall a similar issue where the Paramount was guiding fine for quite some time and then "lost its mind", but I can't recall if this was INDI or TheSkyX I was guiding with....

I agree with you on the advantages of no guiding. It is so much more pleasant to not have to worry about guiding - significant increase in open shutter time for me. And your point about sequencing is so important for remote operations. In my most recent experience I didn't even re-target (plate solve) because over 4 hours the target star drifted only 19 arc sec (0.08"/min), not enough to worry about in my case. So how often do you have to update polar alignment and the TPoint model to maintain adequate open loop guiding?

Sorry for the delay, been super busy since the COVID lockdowns ended here, world's gone crazy!

I update my model probably no more than once a month and that's on a tripod pier, not a fixed/bolted pier - I image I could potentially go longer without an update. 

The Paramount is a nice box, it's not as cool as a 10Micron or a Planewave L350 direct drive, but it's really amazing for 20+ year old gear (with gears!)

I've been using Voyager recently and it has a the great ability to skip guiding if it can't find a guide star (without bombing the session) and it also has the ability to reacquire the target every N minutes specifically for unguided imaging sessions.

Very nice.