I'm more of a feel/fun sailor than super into measurements etc - so I guess my Olympic dreams are over ...
Anyway, my 2c - I have sailed a few SB boards and foils now, including rented Freeride 150 - have found they all work sweet with mast in centre of track, then I make very small adjustments (<1cm) fore/aft
Now use Fanatic Stingray 140 with Supercruiser - it has extra long track, allowing mastbase range from 980 to 1170 from centre of front foilmast bolt - my impression is that blasting foilers run at around 1100 to 1130, tricksters much less - hence long Fanatic design intended to cover both styles - others can help with this if my impressions are way off!
I go with about 1120 from bolt, bringing it back slightly as sails get smaller - works for me at 90+kg, I like to go out powered up, and base forward helps me trim nose down when accelerating in gusts or on a swell
Hope that helps