No reason to spend the money (or effort) of 0/1 to the amps. Run 0/1 to the distribution block and then 4 gauge to the amps. The amps won't accept larger, anyway. Put a big-ass barrel fuse as close to the perko switch as possible. Make sure to run the same gauge for both power and ground (obviously.)
My amps are mounted in the storage space under the glovebox. It's an inelegant solution (it's been on my list for 5 years to build a better amp rack. Right now mine are just screwed on 3 different angles of that compartment and a half-birdsnest of wires connecting them. It's awful, but it works. It's dry and it's out of sight. No other place on this boat has both of those luxuries.
When I bought my boat there was 4 amps mounted to the bottom side of the ski locker lid. Surprisingly, they stayed dry. Not surprisingly, they didn't like running upside down.
Former owner of a 1987 Supra Saltare. Current owner of a Malibu 23LSV.