RE: How do you recommend I seal this?
One more thing. Get some brass or aluminum tubing at the LHS or via Tower, and get a tubing bender and do your own tank plumbing. Just a suggestion. That's what I did.
One of our guys that flys Intermediate Pattern does some pretty elaborate plumbing in his pattern plane. He swears by his method, and he never has a dead stick due to poor fuel flow nor tank fuel foaming. And he does not use a pump.
CGr.