Ed's latest email came through as follows:
"Do not have a brand preference but 3M is good and it could be white and you could use this on the edge of the strip also but make sure it is a marine/RV type of sealant/adhesive.
The silicone is easy to clean off if you get it on places you do not need it and any glue would be more difficult.
Hope all works out."
I think he's talking about the 3M 4200 and 5200. What I think I'm going to do is use 5200 between the two panels (I'm almost certain it is aluminum to aluminum). I think I had better do the other side at the same time. I'll remove the plastic trim and that way I can really get in there and get it all cleaned and distribute the 5200 evenly. I'll probably also remove the plastic trim piece that goes down the center-front of the trailer (at least the top part...the part above the Trailmanor sticker). I'm going to think long and hard about the Eternabond. It may actually do a better job then those small little plastic trim pieces but I'm afraid of the way it might look. If I drop a line using masking tape to line the Eternabond up I think it will look pretty good. Also, the Eternabond will probably allow water to drain off the front of the trailer better (and not trap it on the roof) because it's not be as thick. Have you seen the Eternabond Youtube video:
It looks pretty easy to use and effective.
Thanks for letting me know about the front piece of plastic trim, I'm glad to know this is the way they were supposed to be built. I was afraid the factory had built mine differently then others.
Thanks