I made a little bag with the Seam Stick tape to try it out. This made me change my mind again. This stuff smells terrible. The fumes from the tape irritated my throat and the bag continued to smell bad hours after it was done. I ended up throwing the bag out. The tape is sealed up in two zip lock bags. Maybe I will find a use for it when I can open up the windows in the summer.
I moved on to making a small mocked up sail using a stapler for basting. The household stapler we had already does fine with 4 layers of Weathermax 65.
I made two very small panels but used the hemming and panel seam allowance that I hope to use on the full size sail. The hem is 50mm [edit: not 500. doh!] and the seam allowance where the panels are joined is 25mm [edit: not 250. doh!].
Honestly I am starting to doubt if I can do this. If I made something like the attached photos, full size, would this be a functional sail? I was not able to line up the hem of the foot in a way that worked without a big crease. Basting the panels together with staples went very smoothly but when I unfolded it the whole thing looks misaligned.
I would appreciate comments from anyone who has made a sail with TCPJR methods.