I should mention that I have stretched the Double Eagle 10%. The stretch is aft of the stem, as the curves in the forward section are left per the plans. Only stretch between the transom and frame 6. This yields about a 18" stretch. This is 24' 8" OAL in these pics.
The stem is 2 layers 3/4" ply laminated. I cut mine as whole pieces from (2)4x8 sheets. The plans allow joining smaller pieces to save material, but I dedicated 2 sheets of ply for whole pieces. A moderate amount of scrap comes with this, but I got all the gussets, a scarfing sled, jigs, etc., etc., from the leftovers. The long clean edge from a new sheet of 3/4" ply can be a decent straight edge for the shop. I got one from the stem material, and is worth the price of the sheet.