I've personally not worked with scratch-build before, but "gaps" like that in pepakura can be fixed in the cleanup stage. Overall, I would have to say that it is a decent start. Keep it up.
Wal-mart sells fiberglass, resin, and bondo all in the same section. They are all in within about 3 feet of each other.............typically. Quick question: what did you use for your dome?
Quick update:
ok I found the fiberglass but i didnt get it yet only b/c i read somewhere its best used in 40 degree weather or better but since i live in ohio its pretty cold and freezing right now