Larry, it sounds like your on the right track. As far as the staples in the runway. We ran the top of the staples North to South just like the runway. In 10 years we never had any problems with this. They are actually sunk in a little so the planes glide right across them. I don't think your seaming idea is a bad one by any means. I just don't know what you are going to gain. A few years ago there was a club in NM that used a roofing emulsion to seam their runway. I am sure the post is still here on RCU someplace. There was some contact info in the post if you can find it. It would be interesting to see how their seam held up.
I found this. maybe you can tell if this is the same product you are refering to.
http://www.laaeromodelers.org/galler...ex_runway.html
David