I know you seem to feel you have the composite knowhow to make modifications to your tanks but we've seen a few people that had all the answers hurt themselves and, frankly, we don't need the publicity of another one. I posted your "solution" on the forum you should be, but refuse to, frequent with these issues. Here's some input from a former Scaled Engineer:
- if you've used appropriate epoxies to line your tanks (EZ10/87) then you don't need anything else.
But if you DO want some sort of tank lining, neither polyester nor vinylester are the right choices to apply over the epoxy structure - adhesion is poor to marginal - terrible for polyester, and just bad for vinylester. Use some sort of polysulfide fuel sealant, as has been discussed previously - there are a few choices, under various brand names, such as Pro-Seal, whos PR-1422 or P/S 890 Class A sealants would be appropriate. NOT the Class B, which are not brushable.
https://www.aircraftspruce.com/catalog/appages/proseala2.php
is one choice.
I'm not going to waste any more time trying to point out that these are very different airframes, not boats and not looking in the right places for your learning curve is going to produce something we'll simply warn potential buyers about. Sayonara.