They fit all MINI 17" wheels
R99's are mentioned specifically in the press release:
R85 17" S-Lite Wheel
R87 16" Double Spoke Wheel
R90 17" Two Piece Cross Spoke Wheel
R91 17" 5-Star Bullet Wheel
R95 18" John Cooper Works Wheel
R98 17" Web Spoke Wheel
R99 17" Double Spoke Wheel
In addition the 16" new wheel R94 fits but presumably not the R84.
