I would imagine on a sail the size of you T37, a 5-1 would be nice. I find 4-1 on mine to be more than plenty! And would assume that 4-1 for the OP would be more than ample to, with 3-1 reasonable, 2-1 would be "why bother!"
At least since his main and mine are similar in size, that would be my take on this situation!
Also it is nice to know we can learn things upon occasion too, so I must not be that old of a dog/person eh!?!?!?!
She drives me boat,
I drives me dinghy!