Reviving this thread to ask R9 owners
@Tony's Table Tennis @WingTT @mattlamperouge about how much to boost.
I bought the 40.5 version and right out of the package it's already clearly boosted. Never had a Chinese rubber as floppy and pretensioned as this (maybe Jupiter 3 comes close). I used the durometer on the sponge and it came to around 52d.
I ended up just putting a thin layer on top of the pre glue layer and it gave it a very mild curl. Remeasuring hardness and it's now 51d and I don't know if I want to go any lower than that.
Did you guys notice the pretension and floppiness right out of the package? Maybe the differences in experiences of people might be due to inconsistency in the amount of factory boost? Mine seems already on the high end.