I just updated the Genius CP models to v3 with much better pitch curves. I found this
where they did detailed tests to find maximum thrust and that is where I set the maximum pitch just above. I also made some changes to make the pitch response much more linear.
My flight time has gone way up. Could be because of the motor breaking in or maybe because I'm no longer switching between a bunch of modes testing things. Using idle-up for the whole session I'm at 6 minutes on the stock batteries and almost 10 minutes (!) on the nano-tech's (have to watch your motor temps if running this long; it's reasonably cool outside and my motor barely gets warm).