Thanks for all the info on the fixed throat.
I'll have to do some research on how much the throat-peak tension affects my sail. My sail is cut dead flat (lay it on the floor and it doesn't wrinkle anywhere) and the head is a straight line. So changing the tension along the yard may not make as much difference to its shape as for a sail cut with some fullness.
But I won't know until I test it. So I guess I'll fix the throat before spring and try some different tensions to see what happens.
Thanks again!