Multi-head showers

I'm installing a multi-head shower at my sister's this weekend, marketing says it is a vertical spa. The install directions are pretty specific about balancing loops and placement. I've read on here that the loops aren't always necessary, but it isn't that much more work at this point. Moving on, two questions:
- Am I just safer using 3/4" for everything, even though the heads are all 1/2"
- Can I use threaded copper female in the wall and then brass stub outs, or am I safer just using the bronze drop elbows (excuse if I have it named wrong).

Thanks again for an excellent forum.

should go with the balancing loops. 1/2" is probably going to be fine and use the drop ells

What is the maximum flow of the system? 1/2" copper can flow about 5-6gpm, and a 1/2" valve and supply lines may not be able to supply what you need or want. You'll also need a pretty substantial WH and might look into a waste drain heat recovery system.

The specs demand/call for 3/4" supply, which I've done, doing the rest in 3/4" isn't difficult. I will use the drop ells as well.

The water heater is a 50gal electric that is on its last leg. I'm thinking the AO Smith Vertex...man that looks like a sweet machine.