Gentlemen, Christopher and Ian) thank you for the info (and the pic's). I can't find supplement E so that explains why I was having some
difficulty (more than usual...).  The two tanks (with the slosh door)
are serviced by a single 1/4 vent tube.  The third tank also has the 1/4
tube.  I like the idea of the aluminum plate to anchor the nuts to, and
then the foam with appropriate bid.  I also hear you loud and clear in
making everything leak proof, I can't imagine having to try and fix it
after.

This list is great, thanks to everyone for the help.

Cheers
Doug
1st time 360 builder, 2nd owner.