Suppose I came about an experimental airplane. I know that it is reasonably safe to fly, being flown for a while by several owners, and of course a DAR issued it an airworthiness certificate. Still, I'm thinking about re-measuring and weighting it, then re-doing the W+B form. Given the factual weights and dimensions, how do I find if the CG is within a safe envelope?

I figure that first I need to know where the center of lift is. Can it be done by measuring the wing and possibly guessing what common airfoil was used? If yes, how?

After that, I guess that I need to know where the permissible envelope is (knowing that I can see easily if factual CG falls within it). How do I find out?