Oh God, you're WRONG.So, damn, wrong.
The fuse isn't to protect the amps, it's to protect the wire so that it doesn't catch on fire. When the fuse blows, that means the wire had too many amps running through it and was at risk of catching on fire.
For 0/1 AWG, I'd use a 300A fuse.
You fuse based on the wire, not based on the amps.
Don't post if you don't know what you're talking about.
For the utmost safety, you fuse the wire after the distribution block, for the same reason you fuse the main wire going back... incase there's a surge of amps, your wire won't catch on fire. A fused distribution block does the same thing. If you're going from 0/1 gauge to 4-AWG, you put a fuse the proper size for 4AWG (don't know the # ATM) at the fused distribution block, so you don't have to put an inline fuse for that wire.
And OP: High-end RCA cables supposedly make a difference, although most people with untrained ears won't be able to hear it. I've run cheap-o Radioshack RCA cables in every install I've ever done, and it sounds perfect. The difference in each RCA is based on the material the actual plug is made of, the size and material of the wire on the inside of the wire, and the shield around the wire. (The nicer / thicker the material, the more expensive.)
If you are just running a modest set-up, just stay with your RCA's.