I'm no expert, but I don't believe body wood will make that much of a difference.
Are these passive or active basses, do they have the same pre amps? Pots?
I would be looking at these things first.
I'm sure you will get more opinions, this is just mine, so take it with a grain of salt.
Good luck on your tone quest!
Schecter owners club #205
Hartke owners club#201