Which booster is better for old gen tensors?

E.g. Hexer, I use it on FH now. Speed is not my main concern, I`ve got a fast blade (Nittaku Tenor) and a lot of my own power. I need to soften it up to  help the ball sink deeper into the sponge while looping and gain more arc and confidence. I play in open-air - dust, humidity, cold weather... Rubbers become noticeably harder an lose 'grab' and dwell, ball doesn`t penetrate into the sponge as easy as indoors. So I need to soften it up just a little to regain dwell and control.

Which booster is the best for this purpose?

I remember trying my Falco temp long on a sheet of Mark V. The effect wasn't that great. Whatever effect it generated though, lasted the same time as it would have on tensors.