Hi

Although a high wing trainer with a flat bottomed wing is ok, i'd go for a trainer with a semi symetrical section.

Evryone i have taught with a flat bottomed wing plane always seem to have a lot of difficulty maintaining a constant height due to the trim change at different throttle settings which is far less with a semi symetrical wing.

The flat bottomed section for a given plane does have the advantage of a slower stall speed.

Simon