I calculate all my CG''s with formulae out of an engineering stability text. Except for LEX
With LEX the best I can do is get an estimate. If you have an F-18, then you can just use the CG measurements for another F-18 model scaled to your size.

The YA F-18 balances 12.5" forward of the TE at the root. Assuming your F-18 is accurate, just take the ratio of your wingpan to the YA wingspan and multiply by 12.5 and there you have it.