Just a heads up, the way this adaptor is designed all the vertical loads come to bear on the very top forward corner of the foil head. I actually had that corner chip off the foil head before I realized what was going on. The foil will be okay but I had do something or it would just keep getting worse. I have read about people building spacers to solve the problem. I used packing tape and wax as a mold release on the foil head and filled the cavity in the adaptor with chopped carbon and epoxy. When I pushed the adaptor down the excess filler squeezed out of the holes on top. The next day I used a rubber mallet to hammer the adaptor lose and re-drilled the holes in the top. Perfect fit and the whole top of the foil head now bears the vertical loads.

You might have a good solution.

Physics. All foils, where the front wing is forward of the strut, will want to rock forward. You can see this by mounting a deep-tuttle-top foil (preferable without a flange) loosely into the board (do use a leash just in case). Then foil it. You will see the front screw come up and the back screw press down.

Yep, had manufacture a spacer as well. And sand foil heads to make things fit.

i really think its something the foil and foilboard manufacturers need to work on, so there is a universal deep tuttle and deep tuttle head, with no ifs or buts about one deep tuttle foil fitting another board. All good and well having to sand a fin head to make it fit, when it's just side load. But there's a lot more dynamic load on a foil.

A foil that doesn't fit its box bang on isn't a good start. Its asking for things to break.