The crank rotation hasn't changed any, just the stroke length. So base timing would still be 10*. I'll let the nitrous guys answer the second part of your question. So here's a bump for ya.
I run the base 10 timing but have a superchips chip to add more timing at WOT. I also have a n2o setting that back off 2 degrees. I run a wet kit with 125hp and run 92 with octane booster with no detonation. Hope that helps