I would certainly try any sails you intend to use on the 100% masts.(Before you buy)
Few seasons ago I upgraded (sort of) to 100% (SDM) (From C45)masts for sails 6 to 8.5.(Mixture of Tushingham and Pryde)
Found sails felt very hard and showed no improvement in speeds (GPS) . My 7 metre T Bird actually felt nicer on old C45. The 100% mast also came with a warning not to use in waves (How do you avoid them at coast ???)
Ended up selling the 2 100% masts and settling on C75`s (Tush)
Sails feel loads nicer and I have more confidence in rough water.Yep they might be a touch heavier but ???
I think on really big sails (9 plus) you might be better off with 100 and its stiffness/lightness but I reckon sails under 8metre are still designed around cheaper (sort of) masts.
Think its a different matter for RDM.430 and below I`ve gone RDM (100%) 460 and 490 have 75%`s.RDM needs 100% to get its stiffnes. All sails seem fine on this set up.
There is a lot of Hype around 100%(SDM) masts. I was very disappointed,but my biggest sail is 8.5.