okay after i buld my box i want to put a coat of resin on it just to keep it smooth and ive heard it can help SQ and SPL just a tad... but what if on the baffle... i drilled small holes into it so that the resin could go into the holes to hold on better to the MDF... thats probably not needed right?
Resin is basically a really hard glue. It'll adhere to the wood without trouble. For sq purposes, resin will help smooth the surfaces and reduce the total friction of the system. For spl purposes, it'll strength the walls of the enclosure, causing less resonance of the panels, usually increasing spl.
plenty of wood glue and 2in dry wall screws followed by some inside silicone does the trick very well. no need to resinate your box IMO its a waste of time. just take your time on the glue and well placed screws with a nice bead of silicone all around will seal it up as good as anything will.