The subject refers more to mechanical, plumbing, and electrical, rather than shape/layout. I know this info used to be available in the now-deleted forums, and I'd like to exist here now. I'm considering having a pool built soon, and I'd like to know these things before working on a contract with a builder.

Plumbing:

Separate returns for mains and skimmers?
Size of returns?
Any valves better than others?

Electrical:
Lightning do's/don'ts?

Mechanical:
Steel requirements (in case of gunite/shotcrete)?
Equipment layout?

Please add anything you can think of. I know this is a lot to ask, but we can help new folks with a post referral in the future.

Chris