If you can and are interested get a copy of " Aerodynamics for Naval Aviators " it does a good job of explaining lift.
NAVWEPS 00-80T-80
Patty Wagstaffs plane also has a symetrical wing and flys very well, how the airstream is circulated over the wing is an impotant factor, the chord of the wing where the leadin edge break point is etc. But for a symetrical wing probably the biggist factor is angle of attack.