San Juan 21 Class Association

I'm in the process of buying some new sails. As part of the process I've been given a measurement sheet. The boat is still in storage and I can't raise the mast anyway until I've installed a new mast base and spreaders (see my post re: dismasting from last November).

My question is - the one deign specs for our boats are pretty clear, and my boat doesn't show any signs of modification, do I really need to go through all the measurements?

I am in the same situation. I am not too concerned as I believe the stock measures will be fine, plus there is a lot of leaway with our boats. I took all the measures I could (including of the old sail) considering it is winter and the boat "socked-in" snow. I ordered a Genoa last year from Precision Sails from B.C. and it was good. Now I am ordering a Main Sail from them. I suppose, that if you want to be 100% exact for regulation racing, that you would be in a different situation. Please note that I may be wrong, I am a less experienced San Juan owner than the majority of others on this site.