Originally Posted by EarthBM
Question 1: How hard/costly is it to replace the main with a proper fully battened square-toppish one? Can use the same mast?
That's a pretty radical change that I doubt you'd be able to do with the same mast. The fathead main will put a lot more load on everything.. and I suspect routinely hoisting/dousing a mainsail on what is meant to be an in-mast furling foil will not go well... for best results you need a proper mast section with a sailtrack - and for a large roach full batten sail something like Harkens Battcars (all $$$$$$) would be the way to go.