Any production board is built with team rider input They're the ones that give feedback, therefore the board/sail is optimal for the size of the rider. If you have the same physical characteristic as the team rider the board should be golden for you.
Custom boards are built to your weight/size and perhaps your most sailed location. They would also have the latest proven designs.
I would also ensure it has rails to maximize flexibility in foil placement.
Perhaps you should ask from the following forum as the foiling participant and knowledge is extremely high. https://www.seabreeze.com.au/forums/Windsurfing/Foiling