Hi! Install gaskets where ever you can. They are a good way to prevent potential leaks
. Also the method Per has recommended is good. When I rebuilt our door there was nothing behind the door latch to stop water getting in. Some of the members have had a real problem with their doors being really satuated. If you need heaver gaskets, car tire tubes are good to.
When you are on the road with your tailer, everything is in motion and moving causing the hardward to move and scuff the paint
or gelcoat and elongate bolt and rivet holes. For example, many of these trailers have doors that are drooping, causing a bad fit because the hinge bolts are only through the fiberglass thereby allowing the door to leak. Almost all the hardware I took off on the outsde left scuff marks, some thru the gelcoat. I solved the sagging door problem on ours by welding 1/4" thick alum. hinge plates to the alum. frame I built into the door. No more problem, a least not yet!
As far as the butyl tape still squezzing out, yes that is common for a few days till everything settles and finds it level. You have to realize that you are squezzing about 1/8"tape down to maybe under 1/16". Don't over tighten the screws!
Another tip for you that was on the forum before it got hacked, something that I haven't done yet. Pull off your outside louvered panels for the stove, fridge
, what have you and install some screens in there. It will keep the mosquitos from coming thru there and under the counter and into the trailer when you are camped at night. I have been fishing at some lakes where they could pack a moose away!!!