I'd do it differently
I would set the rig, them position the chocks in the mast partner. First, I'd get someone who has done this to do it with you the first time. Then I'd loose all the lowers AFTER CHECKING THAT THE UPPERS WILL SUPPORT THE RIG. Next, I'd set the mast fore and aft so that a wrench, hung from the main halyard, will hang three inches or so aft of the gooseneck. Move the rig forward by loosening the backstay the same amount you tighen the headstay. Move it aft by revesering that theory. You don't want to pull tension into it yet. Make sure you don't totally unscrew a turnbuckle. Now that its set fore and aft, pull some tension into it. Put on half-turn on the forestay and then one half-turn on the backstay until the backstay deflects approximately 1 inch with a 20 pound push at shoulder level.Next, center the mast laterally by taking your halyard to the portside chainplate. Tie it off. Take it now to the starboard chainplate. It should be the same distance. If not, move the rig side to side by tightening on turn buckle and loosening the over. When its right, put tension into it, one half turn per side at a time until the uppers are also set to deflect one inch with the 20 pound push at shoulder leves. Because these wires are lighter, it will mean they're set slightly lighter than the fore and back stays - you want it like that.Next, tighten all the lowers hand tight. Now pull tension into the forward lowers until they feel just a bit looser than the uppers. Not very scientific but it works. Finally, do the aft lowers until they're not quite as tight as the forward lowers. Now chock the mast with wedges. Don't seal it off yet, but sail the boat. Do any necessary fine tuning. Re-tune and re-chock as necessary and seal the partners.Justin - O'day Owners' Web