Metman: That pool noodle idea is really good. I'm thinking wrap a speaker in plastic to protect the grille and piano finish, wrap with bubble wrap and put noodles on around top/bottom, put inside second box with corner pieces, like you said, and stuff with peanuts or more bubble wrap, for each one. Yes local pickup is definitely preferable.
Gdnrbob: Yeah unfortunately I don't have the original boxes for the quattros, only the solos. I'll check out Uship as well. Also read greyhound can handle some larger items, but like you said it would be good knowing the speakers were being handled by professional movers.
Thank you both for all the help! Much appreciated.