All good points chaps
I started the thread with the hope to get this kind of feedback. Even if all it does is give folk an idea of what to expect with different scopes/sensors, that's interesting and useful IMO.
When it comes to total exposure length, I'm not sure what would be reasonable, again I just kicked this off as a forum to discuss this vague idea (whether or not it turns out to be useful!). I started off with (the best) 16 subs of my first test shots with the 1600. With travels and associated weather I haven't had a chance to use it since. But hopefully soon.
Any suggestions for fainter targets? There must be heaps of southern targets to have a go at that I may/not be familiar with