Best way to figure plan on replumbing my old house?

I own an 80 year old craftsman style house.

I am wanting to replumb the house.

Most of the water lines are the original steel galvanized.

Most of the updating, done by previous home owners, were completed by Johnny Jackleg and his best friend Chip Cheapskate.

The updating I have done, well, I have tried to do it really, really right, even though it cost me alot more money in materials and time.

How do I design the best layout for my plumbing?

Where do the designs come from for new houses? Do the plumbers just start installing pipe the best way, or do they use a print/plans?

Reasons for wanting to update:

1) Some of the old galvanized is going and appears to be past its life span.
2) The hot water pipes seem like a maze and really inefficient. No wonder it takes 27 minutes to get hot water at the tap! I am trying to be more fuel and water efficient.
3) I think we will be in this house for quite some time. I want to prevent plumbing problems before they happen.

I am planning on using all copper L grade (?) (the medium grade). Am I dumb for going this route?

Thanks in advance!!!!!!!

Clove

You might want to investigate Pex tubing. It lends itself very nicely to repipes. Less invasive!

The house sits on a full basement. I have super easy access to everything, except the kitchen plumbing, which still isn't that bad.

Is PEX the way to go, otherwise?

clove

I can knock out a 1 floor 2 1/2 bath with an unfinished basement in a day with PEX.