Want it to fly easily?
land easily nice moderate flying speed --outdoors?
get wingloading down UNDER 5 ounces per sq ft.
We build a shi- pot ful of small electrics - mostly 275 squares -to - 400 squares
The smaller ones work best at 3-4 ozs per sq ft.
Not guessing here - having done lots of em for indoor /outdoor
Tho these are aerobtic - th kids 8-10years old -can steer em around as the speed and maneuverability is nice and easy .
No amount of airfoil futzing will change this - just go for any airfoil strong enough to be reasonably free from floppiness.
a flat plate is as good as it gets .
seriously.