whoever told you they are lighter is lying, because they generally are not. and to be honest, how they feel to grip when waterstarting? since when did anyone buy a mast based on that criteria, however they make buggerall difference to the way it grips when waterstarting unless you have tiny baby hands.

that said, all my masts are rdm's because i want to spend more time wavesailing, and they are more durable in that aspect.

if you are primarily flatwater sailing, then buy the mast that will give you the best performance for your sail, which for a lot of flatwater sails is still an sdm mast.

I can see however that the sails you have are all wavesails and most of them are now designed around an rdm (thou a lot of manufacturers will state that they are compatible with both), so you should probably get an rdm mast. I had a quick look on the NP website to see what the recommended mast for the sails were, but couldn't find the information? but most manufactures supply the info, so its probably buried somewhere on the website.

on booms, you get a rubber shim with most rdm masts, that allows ur current boom to be used with the rdm mast. most new booms come with them as well.

so yeah, get the rdm. oh and you might have overlooked this, but you will need to buy a new extension as well.

I'd agree with that. If you are planning on getting into waves then RDMs are preferred.

You can rig a skinny on an SDM extension if it has a pin or pins for the collar adjustment. There is a plastic cone you can get that sits inside the extension on the pins and the base of the skinny sits on that. Its not a bad solution. Its just a little inconvenient to adjust the extension length.