More questions about dedicated lines

We are moving to a new house built in 2007  and I am fortunate enough to be able to move a wall to create a room with golden ratios. I will need to run some new electric and it gives me the opportunity to run dedicated lines.  I have spent countless hours rummaging through the 7k discussions on this topic and have a decent idea of what is needed.  My plans are to have four runs of Romex 10/2, one each for each monoblock VAC signature 200's, my digital, and my Audiokinesis swarm which has not be set up yet.  I estimate the runs to be conservatively 45 feet including up and down distances. All runs will be of equal length ending in SR  outlets. They will be separate from each other and all other lines and no metal staples will be used.  When I told him I my goal was to have the best sound he offered a suggestion that I hadn't come across in my electrical education here on the gon.  He suggested placing what sounded like a commercial power regenerator with a large battery bank as the first step out of the breaker box and running lines from this.  The other options were to run from a preexisting sub panel that has the pool pump and a few lights on it, but nothing else.  Third is straight out the breaker box.  He wanted to put the runs closest to the utility line in, stating that there will be less noise upstream than downstream, but this puts these lines next to a big double breaker (cant' remember what it is but is sure to be noisey).  He understands that I want all lines on the same phase, or line,leg.  My questions are: Of the three options, which would be best?  Is there anything else needed to minimize the risk of ground loop hum if I use separate hot, return, and gound for each line and not share ground neutrals and keep all lines separated from themselves and other lines.  If going through a subpanel with little on it, how do I manage to keep all runs on the same phase without unbalancing the breaker? A third tangential question-Is it best to use metal or plastic housing boxes for the receptacle? The question of durability of the plastic fatiguing and breaking following repeated plugging and unplugging has been mentioned but I didn't see an answer.  Finally, a huge thank you to jea and almarg for their voluminous responses in all the prior electrical discussions-I got an education.  Sadly, I still don't speak electricalese.