unfortunately thats where qhy5 and ossag stop being useful when you have >40mm aperature to play with. When your talking OAG with a 10mm pick prisim/pick mirror on the edge of your fov aka only getting about 80% illumination they start proforming poorly.
I have no experience with the new SBIG STi but the 402me is a huge beast of a guide camera but extremely sensitive! I normally run at anywhere between 0.5 -2 second exposures depending on the seeing.
The Load star i have seen in action and well when your doing AO (which is what it is made for) it picks stars at i think upto 10Hz off an oag.... if that doesn't speak volumes then nothing will.
