I think it flys 'dirty' without the cowl, but there are many here that never installed it on theirs with no problems. I think with the 100 it would be safe to start with 3 degree and if you have to add or subtract it will only be within 1 degree so the line up wouldn't be off by much.

I slaved my ailerons to my elevator yesterday 'flaperons'. I found that it was more effective in KE than with the elevator slaved to rudder. Made for some tight loops as well, just like a huge foamie. Joe