See table of measured tensions for some ballpark ranges.
Adjusting the standing rigging
I set the mast as far forward on the base as possible. The I use the main halyard from side-to-side to make sure the mast is in column. There is no rake fore-and-aft. The mast is in column.I tension the uppers with about the same tension keeping the mast in column. Once sufficient tightness has been achieved, then I tighten the forward lowers enough to pull the center of the mast a few inches. The aft lowers are tighten just enough to take the slop out with no real measureable tension. What happens is the uppers are all about the same tension, the forward lowers become the most tensioned shoudls and the aft lowers are the least tensioned.
- -- Mike Lehman (from the public-list)