Hey Joe, I see you have a lot of solid advice already.
I would suggest going with the bigger board to start with. I reinforced the deck and bottom of my old formula board around the box with 3 layers of glass but it may have been over kill.
I think you will find you will need to run the mast track at the very back and you will find the foot straps in the wrong position. I am a bit of a contrarian but I would suggest taking the straps off and staying near the centreline of the board to begin with. I found it easier particularly when I started to try Jibing after a couple sessions.
Oh also go with a bigger floaty wing (+1000 cm sq) I know may folks that started with the smaller wings and switched to the bigger wings and have never gone back. Unless you are planning to race the bigger wings are the way to go.
I must say that my Custom Roberts Foiling board I got this fall is way more fun than the formula board and worth the cost, but I still ride without foot straps. Not good enough to use straps

Hope this Helps