Rocks are designed to be used on RDM but I`ve found I need to change down earlier when rigged on RDM as opposed to SDM.Similar story with Search but suspect that been an older design was intended for SDM.Rock rigs on either. (In theory)
End of day we use what suits us. I sail waves/bump/jump all time and have yet to break a Tush 75 SDM. Last season all my Vmax`s were recorded on SDM and IMO sails have a larger wind range when rigged on them. Do suspect weight has a great deal; to do with it. At 105k I must be putting at least 30% more loading onto kit than Davide (at 70k). I can see great lines appearing in Rocks(and Search) when on RDM and overpowered.
I would never even consider a 460 RDM. Might even sell my 430 and 400 RDM`s from experiences I`ve had !! Cant see point in having a tougher mast if it results in a less efficient sail.. Before anyone buys RDM I would recommend you do a bit of testing with your rigs (at least rigging on them) before you commit and buy them.Especially if you are heavy.
The whole IMCS is thrown into disrepute. Compare even a 45% SDM with a 100% RDM and I`ll bet the SDM is stiffer !! (And probably as light !!!???)
Slightly off topic but has anyone felt the weight of Naish RDM`s !!! They are unbelievably heavy !!! Perhaps they are as stiff as claimed but should be at price they are ???