Thanks Kevin. I'm actually using the stock focuser (figuring that it's a false economy to upgrade the focuser on a $550 OTA). It's not ideal, but with practice I've gotten quite used to 'tweaking' it slightly, and so can still use it relatively effectively with a bahtinov. As you can see from the stars, it works! (albeit rather fiddly).
Basically, I've concluded that this scope is a pretty darned useful narrowband imager at f/4. I tried the RGB experiment with it and was really dissatisfied (blue bloats, red swells, green is small), so I won't be revisiting that setup. But for NB, it'll probably see a lot more use, as I can keep the subs relatively short. At least until I purchase that WO FLT132 that I've got my eye on...
