Paducah - It's complicated. I had previously adapted the mast to fit an Axis fuse.
There's not much to show now, I drilled another hole in the Simmer fuse to align with the rear Axis fuse hole. The front hole already aligned.
Then I epoxied it together because I couldn't be bothered trying to shape another friction fit and I thought the permanent connection would be super-stiff

720cm2 is perfect for higher wind in swells if chasing speed. The 550cm2 works surprisingly well too but requires more effort to keep speed through the gybes.
Both require gentle foot movements mid-gybe but easy when you get the hang of it.
I reckon the board is about 85 litres not 90.
The possible downside of small board, small wing is having to sail mostly a little overpowered to ensure waterstarting and getting up on foil.
Worth it - when the wind is reliable