Just a thought (have done in other cases but not this) is to use a clear dielectric compound to fill in any gaps. It does not harden, can be removed, and is water proof. In this application where there is the potential for water seepage but no direct stream with pressure, it probably would work great.
I like this, it might just work.
I didn't know if I should double-up on the lens-to-bucket seal, which would push the thick body seal further out of the bucket assembly. Wasn't sure if I should add some sealer between the thick body seal and the body?
Double sealer gaskets work, sometimes, I've done that on a Dodge. Give that method a try. I've noticed that some aftermarket gaskets are an open cell type while originals were a closed cell. What were the originals, and what are the replacement materials?
Another thing to try is Scotch Guard fabric sealer. I spray it on the 64-66 defrosted ducts and plenum as a moisture repellant. It is a clear spray. It might repel water on the sealer gaskets.
Another consideration is strip calk. I can think of a few other sealing methods, but my own personal methods require doing nothing that would be difficult to reverse or clean, like weather strip adhesive (like 3M 8008 or 3M 8001).
Jim