The board: 210L is big. Here a beginner board volume (L) starts at (rider’s weight + board weight = 30kg +20 in kg), so 120-150L and wants 60-70L after 10 hours of practice.
@Michion project should help you. He has reached 41kmph with his 2018 NAISH Thrust WS 1 Foil
A standard tuttle is not IMHO the best option because not much room for 3 motor cables + water cooling pipe. Possible though, here @Clarin using a KFBox (smaller than tuttle) from Alpine Foil:
Your standard tuttle mast head cost 85usd here:
Foil: for 155 + 170usd, you can nearly get a brand new foil in other brands. If you like NAISH, try to find a sale 2019 Thrust WS (WindSurf) foil 1220cm2 : here 575usd new (windsurfing black and orange). Prefer the WS to the KS (Kitesurfing foil) or the Thrust surf foil (big and slow)
A sale WS1 from 2018 (black and yellow as above) should be even cheaper…
They are using mast plates.