Boosters, what to choose?

[Haito]

The R9 has been boosted with yellow or black ?

Kailin. I do not have opened bottle of nat yellow. The nat black I borrowed from a friend.

 

[Kilogramme]

Tell me if you boost your next sheet of R9, with which booster, and your reaction/feeling afterward please. I have gathered more infos on the Jiechie on french forum, and people (multiple) share the experience of "I did not felt the need of reboost before 3 months". I am checking if the effect is strong or not, how many layers etc...