I'm not sure why they want to raise mast and hence enlarge sail area higher up. This would cause more healing and in my experience need to spill wind is a greater issue with the Mac. That said the M mast is slightly taller but compensated by greater fixed ballast. The foresail is however a problem since it is easily shaded by the main and also catches on the guard rail. Is love to fly it higher if the fractional mast could take it. I note that Glyssandra a Mac X has a higher hound on the mast and a really nice tensioning clasp at the bow attachment. I may do the same.

Roly