Keep in mind that if you twist in washout that it becomes washin when inverted. A aerobat machine is best if it feels the same upright and inverted. The twist would not allow this.

On airfoil thickness, many years ago there was a design trend toward thick airfoils. There were no snap maneuvers in the patterns at that time. Some airplanes went to 18-20% thick with a big leading edge radius. The Tarus is an example of this. Wether or not the goal of constant speed flights were achieved I am not too sure.

With the present day emphasis on snap maneuvers (neat stuff) the thicker airfoils are not going to deliver any performance improvements.