Over thinking fuel tank replacement

[CaptMick]

Ok, waiting on the new tank to get here and I am starting to way over think the install. I have a tub under the deck plate that holds the tank. There are no drain holes in the tub. The tub is gel coated. The old tank had the tabs for mounting and foam on all sides but not the bottom. I thought I would re install the same with the exception of coating the new tank. In the past I have used either coal tar or truck bedliner. But reading all the stuff out there makes me thing I should not coat the tank, I should not foam it in and I need to make a way for air to flow so moisture will evaporate if it gets down there.
May be even a drain hole.

Any thoughts? I think I am way over thinking this. The old tank was in there for about 25 years from what I know about the boat. Even if it was replaced in the 90's prior to the boat being refit then that tank still lasted like 10 to 15 years.

Help is appreciated. Thanks,

Mick