Dave,
Go for it. The mast is not likely to be so far off the specs of a current generation mast that you won't be able to tune it. If it is a little soft it can easily be stiffened with unidirectional carbon strips. If your spreaders are not adjstable, you may need to change them so you can tune the rig. If you gave bend numbers to a sailmaker like Jay Glaser or Tony Arends you could match a sail to it. Actualy what would happen is they would tell you haow to set up your mast to maximise the sail.

Good Luck

Eric