Thanks for the encouragement folks! I considered PVC, but figured copper was safest (from shattering, big swings in temps in the northeast) and of course copper is corrosion proof from moisture.
I do have a big question on the end outlet. Most of the filters and regulators look like they are 3/8 inlets & outlets which seems to defeat the purpose of the 3/4 piping I'm using. Any recommendations? Also, do I need multiple outlets for different uses such as painting on one outlet and tools on another?
Thanks for any advice.