I hadn't thought of sum stacking the live view video for planets--just assumed it wouldn't work because it was too bright. That'd be an interesting use case.
I am surprised ISO is working in MSC mode for you guys. For me, it says it changes, but when I go to the images, they're reporting the original ISO. The camera will change to the ISO if I unplug it and plug it back in, but that's kind of pointless. There's an old ISO issue in pktriggercord that they could never resolve, and I just assumed it was manifesting itself here.
The Ekos autofocuser routine relies on getting FITs images from the driver. Because the driver takes a long time to convert the image to FITs, the autofocuser routine is unbearably slow on anything less than a RPi4 (which makes it annoying slow instead of unbearably slow). So live view is nice for at least getting close. As is the ability to take a lower resolution picture in PTP mode, since that speeds up the FITs conversion.
(Hmmm, I did just have an idea though--I wonder if I can could add an option for the driver to downsample or clip the original image before FITs conversion, to speed things up. I'll add that to my list of things to look into).