I recently brought a Severne 90% 430 SDM for my 7,0 M5 was using a Maui 100% didn't rotate well due to its wider profile on the maui bottom cam s ,90% Severne .it rigs perfect ,sail s perfect .fantastic mast .I went for the 90 because of excessive cam wear on my 100 % 460 and 430 .maui ,the protective layer on the 90 I am hoping it will hold up a bit better .for sure the 100 will have a quicker return and if you are a pro rider or racing I would go the 100 ,but other wise a weekend hacker and wanna be GSP freak like me I'm happy with the 90 .and the extra strength made my decision ,its gonna be way better than your 75 % by far .
flip a coin ...

...both are great mast .100 % is top of the line

and will feel amazing on many sails .