There are many good solutions offered here, but none are perfect, they're all compromises. It occurs to me there is no perfect mainsheet set up. As every boat and sailor is different, the best you can do is find a set up that works best for you.

In my case, I've removed the mainsheet track in prepartion for tearing out my cockpit. As I can start fresh on my mainsheet configuration in a new cockpit, I've been sketching and trying different layouts while in the cockpit.

The original leads back to the mast and runs through a wooden curb that the dodger snaps to. Only I know when that is a good a location, and when it isn't. I spend a lot of timing looking at it and thinking, it's not a good location. As I sketch, mock up new arrangements, I see when it is the perfect location, and when it is not.

I think a racing cockpit would be easiest to set up. Then you know crew size and what stations they'll take. A coastal cruiser on the other hand is tougher. Good luck!