It would take two people but, I would make a basturd string and pull the prod up to what the brace should be. Now is when you need the other person. While you adjust your pull to get the brace height he,or she could measure from nock to nock . I wouldn't be afraid to go slightly longer , say 1/4 or 3/8". Reason being you can twist to make shorter ,but not longer. I'm an older archer and I help out a few that either can't afford to buy or just want to rebuild an older bow. I would use Dacron material. You can buy it off the net if you have trouble finding it. I would also add that cheap poly bailer twine can be used for the try string. I do it a lot. I'm not saying everything I do is perfect and completely up to spec. I'm saying use your head here.