Recently (last two years) replaced the main sail (North) of a Ranger 26. Like you, debated the headsail or main and elected to go with the main.
A couple things relating to sailormon6''s response. I like his selection of the racing shelf. I opted for a loose foot and I don''t like the stress put on the outhaul rigging and the cringle. Everything rides on these two items which have blown out on a couple of other retrofitted loose foots.
I was talked out of high modulus fiber sails for the main by the loft. Good choice, sail is too small to seriously be affected by stretch. And the hi mod sails still haven''t demonstrated 20+ years life expectancy like Dacron.
A couple of more items relating to mains that you must address are the increased roach of today''s designs and batten design (full or deep). Not wanting to switch to a car setup at the mast, I elected for a deep batten in lieu of full.
Big loft vs little loft. I used a big loft (UK) and the service was great, but I think having the loft within throat grabbing distance is the secret and size doesn''t matter.
All said, it was the best boating money ever spent. Never realized how much weather helm and degrees off wind I was getting with that original old baggy main!!