It could prove that two pieces of wood can sound similar.
Yes, that is the entire point.
It could demonstrate that those two basses sound alike.
Again, that's the entire point. And perhaps you didn't notice, but they aren't "two basses". It is the exact same bass with the body swapped. If you want to compare body wood, then that is precisely how to do it: pickups could sound different, the necks could sound different, etc.
Dan has addressed your third point already.
Again, props to Dan for an excellent thread!
