Andreas,
Great question!! My uncle and I have talked about this and have thought to trim the airplane to fly on the standard RH prop, then put on the pusher. The thought here is that the pusher may mask some trim issues.
If you have a trimmed airframe, adding a pusher will increase line tension over 45 deg. The vertical 8, Hourglass, overhead, and 4 leaf clover are the maneuvers that benefit the most. I really didn't notice any diferences anywhere else.
Archie Adamisin
Muncie, Indiana