Not a M3 but I went from SDM-RDM in the Overdrive M4 7m , I don't have a Severne mast so just played around with what I've got, initially rigged on NP SDM 430 and the sail rigged and worked quite well, the RDM is 430 P7 the sail set nicely and felt great on the water very stable and had just as much low end power and top end speed as the SDM mast.