Ramona said..
I would suggest contacting Tony Bull of Bull sails in Victoria. He is Galatea on this forum. Tony builds sails and also has sails built in China like most sailmakers do. He will have the measurements most likely but also will offer advice on what materials to use for your intended use.
Also there is eBay. The Cav 26 sail plan is similar to all the other quarter tonners of the era and if your sticking with hanks there are heaps of secondhand racing sails to suit. I had a M&W 26 and used to buy sails off eBay. Laminate headsails off big trailer sailers etc. I have a good mainsail in Dacron that will probably suit too.
Tony is presently at Lake Garda coaching the Aust Int Cadet team at the World Championships. Tony coached last years World Champions.
I understand that with the dollar at is current value Tony is assembling his sails in the Geelong loft from computer designed and laser cut components (imported).
Support your local, it's worth the service.