THE WALL---Why?

It is mostly the fact that power conditioners or whatever you want to call them have a maximum current capacity and amplifiers need a lot of current. Regenerative power supplies have rather severe limitations for maximum wattage and can be damaged.
 I use a Monster HTS3500 and find it sounds much better if I plug my amplifiers into it. It is very synergistic like power cords and is up to your own ears. Each device ought to have its own recommendations and parameters. Your results will absolutely vary.

I am one of those audiophiles who have gotten excellent results when using an over-speced PowerPlant to clean and buffer my wall current. I've tried it both ways, and I vote AMP plugged into the regenerator. (By over-speced I mean my equipment draw is a max of 750va while the power plant can deliver 1500va, so I have 50% headroom.)

dentdog, I think that 20A should be, how to say it, ample. Doesn’t hurt to over-specify, so long as the equipment doesn’t make an intrusive noise where it shouldn’t.

That’s what I would do.