OR preferably... depending on your preference...

For what it's worth I did make a hatch but found my battery (a 1650 mah) was too wide to sit comfortably.

I cut 2 pieces of 1/8" balsa about 1" wide and long enough to cross the fuse and butt up against each side. CA'd each piece on each side of the former that was near the hatch, and used the "stuff with foam technique"

I went to the extra trouble of the "battery floor" to keep the battery area small enough to compact the foam tightly.

I jammed my throws as far as they go and found them to be too much... I was able to get it to snap out several times... which I didn't like none too well...

I guess another moral... DON'T tweak your CG AND max your throws at the same time...