My guess is the tape's role of creating a thicker shaft will play a part in making the racket feel stiffer? Which I assume is because the racket is less aerodynamic, and your swing speed is slower and therefore the racket feels stiffer.
Try 2 layers of reinforced tape, one wrapped (as tight as possible) clockwise, the other anti-clockwise, with a 25-50% overlap. At most the shaft width will be increased by the thickness of the tape x8 which is probably 1mm overall. Shafts vary from 6-7.5mm and those aero differences are negligible. The further the air resistance is from the fulcrum, the greater the effects felt will be. Therefore the top of the head being thicker will have more of an effect than the shaft. It is essential that the adhesive has to be able to withstand the flex plus the tape be able to stretch and compress a little. In reality the shaft is only flexing a small amount, it's not like you are trying to go from a shoelace to a solid steel rod. It's simply about limiting some of the already small amount of flex. Oh, screen protector tape is the same or similar to "helicopter tape" but it can be thick and might be too stretchy.
Wouldn't that also effect the snapback and thus reduce the repulsion force? Seems like you would sacrifice performance just for a slightly stiffer feel.
i guess it's a bit of an update, I found out you can actually make a racket stiffer by adding a layer of clearcoat on the shaft. This will make the racket slightly heavier no doubt, but it's something that crossed my mind when a racket reviewer compared two identical rackets but one came with matte finish and the other gloss, and they said the difference is one layer of clearcoat. Apparently the gloss one played stiffer, maybe people with experience in custom racket paint jobs can confirm this. Either way I'm planning on trying it out on a BS-12 one day, worth a shot imo.
