For the application I used a one inch watercolor brush that I got at a local art store. It wasn't cheap but it's really nice and if you take care of it it will last a long time. I used the same brush dry to help lay down the fiberglass before wetting it with the poly.

For the seams you want to cut enough oversize so that you can overlap the top and bottom piece by about 3/8-1/2 of an inch. On smaller parts like ailerons the overlap is much smaller. This doubling of material will not show up in the final product as the glass is very thin and can be sanded smooth easily.

scott.