I experimented with the flying stab about 5 yrs ago on a 3D foamy that was giving me trouble where, on a tight loop, it would go around steps, as it it felt like the stab was flying, stalling, flying , stalling etc. Mind you it has about 60 deg throw. At any rate, I went to Google and did much research on the flying stab. I ended up with the recomended pivot point at 25% of the surface area. It will now loop without the steps and loops around the wing CG. No signs of flutter at high speed, which isn't much on a 3D plane. Maybe 50 mph. Pivot in the fuselage is aluminum tubing and the spar into the foam stab halves is close fitting carbon tubing.Getting a bit loose after 5 yrs but still no flutter. I think more because of the proper pivot point. Just a regular small servo as with the erea ahead of the pivit point acts like a booster tab. Doesn't look like much but it works.

Gord.