I am no rigger but why on earth would you want to use 3 strand or nylon? That is dock line. If you are concerned about shock loads, don't use HM line like Warpspeed.
Use some 7/16 Sta-set or XLS. Your boat isn't that big, is modern, etc. I mean, you probably have an aluminum rig. Mine is wood, my sails are bigger than yours, and I use 7/16 XLS for the mainsheet. Works great. You really don't want that much stretch and 3 strand just won't run nice.
As for the 2000 pound load on a main, if you have 4:1 blocks on there that means you are pulling with 500 pounds, which is 10x what you can pull.
Allen
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