At very low Reynolds numbers the flat plate is at least as effective as a good design airfoil. I know it sounds strange but in all the books I l ooked there are only 5 airfoils tested in the wind tunnel for small Re and the flat plate is more stable, the separation point is almost independent of Reynolds.
All airfoils with thickness have a hysteresis and for Re=40000-80000, Cl drops significantly (20%-40%) with 1 degree variation of AOA. That's why the wings are rocking so violently.
For a 3D foamie you want to fly slow, the flat plate ( with or without curvature ) is the best airfoil money can buy.

Boby