Yes, you can run a 4 gauge, then distribute them into the amps. From the fused distro block to the amps, I would use 8 gauge. 12 gauge is too dinky. And for the few feet, you should have no other excuse not to run the max of 8 gauge. Whatever your power wire is...it should be the same for the amp. Run 8 gauge out the amps into the chassis. You can use the same point if you like. If you want to be neat, they make grounding distro blocks also.