Keith, I would be keen for this info as well as I am currently having a new sail made. Do you have image of the insignia? There is a great photo in the RL28 Test pdf on this site that you may be able to use to work out the dimensions approximately.
I ended up just giving my sailmaker the photo from this site and he made an insignia up based on that. Looks pretty good. I will get some photos when it's on the boat. I can measure the dimensions for it or maybe he has it on his computer?