RE: Foot Strap Positioning
Try your 8.4 m2 rig with the mast foot a little further back.
Not sure if you are a heavy guy or not.
If you are lighter, and not trying to "race" the F-Type against the Formula sailors, then try moving the mast foot nearly all the way back and get the board to tail walk. Then micro adjust the mast foot back forward until the board is just controllable. Should be very fast and loose set up like this.
You are correct, I've sailed a few Protec's. John liked to put the footstraps right out on the rail and have you "wrap your heels" to push across the top of the fin.
Perhaps it's something you will "adjust" or get used to.
My personal "secret" to tuning the F-Types, is to use the smallest fin you can get away with. I go all the way down to 50-52 cm Debo Concepts on the
F-Type 148. Wickedly fast with a 6.5 m2 rig.
Becomes a "Magic Carpet ride" on really flat water in around 18-20 knots.
The larger 63 cm fin you've got will help with early planing on your 10.0, but you may find it's a bit big, real soon (wind speed around 11-12 knots, board speed around 20-24 knots.
Unlike it's formula "bretheren" the F-Type 148 seems to like smaller sails as well as smaller fins.
Give it a try with the stock fin (or a smaller fin) and a 7.5 m2 rig. It will shock you with it's reaching speed if you get the mast foot nearly to the back of the slot so the water exits from under the board at about the front of the BACK footstraps.
Hope this helps,