Lester,
I am not at all sure if I would recommend shortening the Nonsuch’s original mast by chopping it off in the lower end. The bending moment at the partners, needed to heel the boat over to 60°, is the same, whether you use a long or short mast, as long as the boat is the same. (same beam, weight and ballast).
There is an alternative to spilling winds by bending the mast: Ease the sheet and/or drop a few panels. If you on a fine Sunday come pottering downwind, and don’t notice the grey-black wall of a thunderstorm coming up behind you, you can still save the day by just dumping all but the two top panels. Makes you feel lucky you have a junk rig...
Arne
PS: BTW, the sail I sketched for you is just about the same shape as the sail of a former boat of mine, Johanna (SA=48sqm, B=5.80m, AR=1.87). She worked well with that rig.