Regarding the Blade RB, an sdm mast is likely to add to your efficiency upwind, and general acceleration, and it may prove better in the low end.
Blade RBs include Tekcams for both RDM and SDM masts. For our Blade RB designs (specialized for long raceboards with centerboards) it is likely that SDM will offer the best competitive rig. It may be that RDM and BICO are preferable for lighter riders and upper wind conditions."
Blade RB 2012 specs:9.5 m2 -5 battens plus Sensitip, 3 cams.
Mast: 524 cm.
Boom: 244 cm.
Recomended mast leght: 520 cm
8.5 m2 - 5 battens plus Sensitip, 3 cams.
Mast: 494 cm
Boom: 235 cm