Mono blocks on different phases of the sub panel?

I agree with dedicated lines, but disagree with splitting the amps on two phases from the panel.

I prefer the "high" side of my 240 Volt drop for all four amps. The high side meaning one phase measures 122 volts and the other 119 volts. The 122 runs everything in the stereo and the 119 supplies the refrigerator and all other noisy items in the home that might operate when listening to music.

If your panel is being rewired by an electrician it's fairly easy to do.

Looks like you, Slipnot1 and I all have the same idea.

As for panel, I went with the Square D that uses bolt in breakers (as opposed to snap in) and it has copper bussbars.

Let us know how you do with it.