i dont have experience with unifiber masts. but i think its useful to valuate, ALL the sail makers' top racing sails are very mast sensitive. not just because a different characteristic mast kill the performance and the fun feeling of the sail. but you can have camber rotation or camber jump off problems with a different diameter mast too.
if you want to take the 100% speed and performance from the sails always worth to take the recommended mast - in this case the severne enigma.
if you dont want to compete with it just have fun and you want to save money i would prefer the severne blue line (75% carbon) for you. the characteristic perfect for the sail, about 10% heavier and little bit slower than the enigma, but im sure you wont feel that different when you want to have fun.
with the blue line you make much smaller performance and fun compromise than with a probably wrong characteristic 100% carbon mast for sure. on top of that i think the 75% carbon mast will have better price than the 100%.
i hope its help a little bit,