[K.Porter]

Yes, as has been stated previously: #6 awg, please!
That 12 gauge will go up in smoke if you actually run all the victors in that configuration.

You may also want to plan on switching some of the leads to the Victors over to the other breaker panel. Many of the motors you may use only draw 20 or 30 amps, and those breakers won't fit in the 40 amp maxi blocks you have now.