Welcome to the "Giant Killer"

From experience....don't ask how I know....

Sqare tops are the way to go, BUT reenforce your
hulls. Install an internal bulkhead just forward
of the FWD crossbeam, will help with the stress
loads from the increase in dynamic lift. Go with
the F18 or N20 Spin. The Tornado Spin is waaaay
to big.

This is MY opinion....YMMV