Battery Box Query

[BlueSovereign]

I've just had some custom-designed wooden battery boxes made.

To eliminate the need to lift the 12v heavier ones (for my Genset and Engine) within a very confined space, I had that box made with a removal side (which is secured by 4 SS bolts) so that the batteries can be "slid into place" rather than having the very difficult task of trying to "lift" them within that very confined space (trust me this makes total sense).

While all my batteries are sealed AGM/Gels, I suspect (though don't know) a NZ Cat1 inspector will still expect the box to be sealed in some manner on the box/removal side area. Thus, I need to have some sort of gasket between the box face and the adjoining removal side face, that would I assume be "acid resistent".
Anyone have ideas as to what I might use?

My one idea to avoid the "gasket" approach above was to simply fiberglass the 3 sides of the box face and epoxy resin the adjoining removal side face and allow the tight securing of the bolts to form a "quasi-sealed" joint. Any thoughts on this idea as well?

BTW, all the interior joint areas will be epoxy resin sealed, and the external corners (as per N Calder) fiberglassed.