Sorry, one more question.
Should I use the 3/4" PEX for everything? My inlet pipe from the well is 1" PVC. Is there any reason to use the 1/2"? I would think the bigger the better (inside walls/attic) then reduce down to whatever size the fixture (sink/toilet/etc) needs. This should give me the maximum water flow at my shower head - right?
Since I'm on a slab, everything is currently underground. But to repipe, I'll have to run all the new PEX through the attic. I've read that I should insulate my cold water piping or I will never have cold water at the tap (Florida house). Sounds right.