I mean unless you have schlieren imaging or some other test set up that allows you to see the air flow separation all of this is hypothetical or speculative at best. Again, the smaller fletching benefits are fairly intuitive, the turbulator is a stretch for me. Also, while we are speculating let me speculate. I would say that I would not think that you would just need a piece only in front of the fletching. If you only had 3 single pieces in front of each fletching you would have a mixture of turbulent flow and laminar flow. You would then have three smaller flow separations and then still have a larger flow separation from the arrow at the end. I am having trouble speculating how this would be beneficial. Naturally, (without a turbulator) your turbulent flow separation will occur a little past the end of the fletching/arrow and using a turbulator to create flow separation ahead of the fletching would cause the flow separation before the end of the arrow. Making the turbulent flow transition sooner would increase friction drag which may contribute to the smaller vanes ability to more effectively stabilize the arrow. Regardless, I am still not convinced the that would make a noticeable difference but it is interesting.