Did you ever figure out the issue regarding alpha here? I am trying to render an alpha channel in a similar fashion and found this topic. Curious to see if you figured out what was going wrong?
It seems like the levels in the output are severely blown out; if I use a Levels COP inside a COPnetwork, I can set it to something that works. Ideally SideFX already knows about this issue and has fixed or is fixing it (I’m still using an older H18 production build).
P.S. I should also mention the SimpleBaker doesn’t actually display a debug view for me, though perhaps that’s just my older machine not playing nice with graphics drivers