Yes the bubble version of the winglets give me a steadier flight.
I personally think that it has something to do with the aerodynamics since the bubble version is smoother compared to the regular thin fins wich are noticable nervous during turbulent weather.

I tried different styles with the thin fins, toe in and out and straight.
Also experimented with height and dept.
Because I fly a bipe it is more work and harder to notice the differences.

The bubbles on the stabilizer give me a big difference in loops the tail of the plane tracks better.

I would also like to try a bunch of small fins all over the wing.
The Mitsubishi Evo 9 inspired me, they say the car is more stable at high speeds.

Another experiment i would like to try is make a 2m F3A plane fly like a indoor F3P plane by creating more drag with brakes on the wings.

Just some thoughts