alternative shell to subfloor to frame interface?
I'm starting to re-work a 63 globe trotter that has been severely neglected. Amongst everything else, I need to replace the sub floor and have started the prep. I am working under the assumption that I'll be leaving the shell and belly pan on. In the near future the trailer will be used as a live in job trailer on the northern Oregon (wet, windy and wet) after that I hope to use it as intended. i have started addressing known problem areas for leakage (seams, penetrations, and windows) But have little faith that my efforts will win out over nature. I'd like to allow some level of internal weeping in the walls as a concession. I am considering placing steel shim plates between the frame and alum. channel, these shims would be welded to the frame and screwed to the shell channel(and drill additional weep hole though the bottom Channel towards the outer edge). Next I'd put the interior skin back on and install a premium grade plywood deck holding the decking back from the shell by, say a 1/4". then using an alum. L profile ,screw to the sub floor and rivet or screw though the L into the interior skin and perimeter C channel, to tie it all together. Are there any fatal flaws I might be overlooking?
Note that I'll be stabilizing the frame as I go ( neutralize rust, reinforce problem welds, re-painting) and as for floor insulation I'd like to go with a rigid insulation so as not top have to worry about sag or trapping/wicking moisture as much.
If this has been covered elsewhere, I didn't know were to look.