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On the plumbing question - I would go with a crimp PEX system - no doubt about it.
You will either have to purchase, rent, or borrow a crimper, but, even if purchased, the crimps make economical good looking connections.
The heavier, thicker "snap Pex" connections (the gray ones) use thicker PEX and just look bulky.
I would think that 3/8" plumbing throughout would deliver sufficient quantities of water, but you may want to explore what the line losses would be before deciding on just one size.
The flexible PEX comes in red, white, and blue, allowing color coding for various lines.
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