Hannu specs 3 temporary braces to help get the proper loft on the hull.
They are removed after most of the work is done.
A couple of notes... We found the 6 footer was too tight to use all three braces. Ended up with just the middle brace and that was inserted after the transom was screwed in place. Not as spec'ed but worked will witha graceful line. The 7-6 hull bent fine with all 3 braces in place. This photo is of the 6 footer and the forward brace was removed before bending and not re-installed.
If I was going to build a lot of these (and I might) the fore and aft braces should have a compound bevel. Single bevel worked, but matching the hull sweep in both directions would be better. The amidships cleat is fine with a single angle.