So after an email exchange with Brandon Petersen at Kitfox, I’ve gotten this figured out. Thanks Brandon! I thought I’d share it here in case any others are having the same issue. Brandon said that he has seen those angles to be a little off on some mixers and to just split the difference. He also said that I would get better results if I adjusted aileron linkage on the mixer assembly to 3.7 inches as opposed to the 4 inches stated in the manual. This improved things a lot. I ended up with the left bellcrank at 26.8 and the right at 30.4 degrees. This did require that both aileron connect tube rod ends be adjusted all the way out until the witness holes were “just” 100% covered. BTW, this 3.7 inch adjustment only applies to the STi. Reference page 34 and 35 of the final assembly chapter. Hope this helps someone else.
Paul
Building STi
Rotax 915is
MT Prop
Oratex
N951CT