RE: Box tape on bottom of neptune?
If you DO use tape, get the good stuff at a real shipping or office supply store. Cheepo stuff at WallyWorld has much less adhesion than the good stuff. Start at the rear and work toward the front so any seams will be shingled appropriately.
I was flying my Telemaster on foam floats one day, overshot the landing and hit the riprap. Granite is stronger than balsa and styrofoam. It Gashed up the bottom of one float pretty badly. But since they were foam floats and could not sink, I just taped over the damage and kept flying.