Shower Rough-in Valves Plumbing

This is the third rough-in valve I've had set, by 3 different experienced plumbers (ok one was a handyman), and none have been set correctly. The valve needs to be set at the correct depth. Usually they provide a plastic guide (see below) that should be flush with the finished wall. Figure 1/2" for backer board + tile thickness + thinset, so around 1" off the stud. The Price Pfister fixture is less than an inch so putting this flush again the stud is almost certainly a mistake. Mine was set too far back but fortunately it still works. I had to reverse the cylinder that holds the plate against the wall and it shows the valve when water is turned on. Next, it should be perpendicular with the wall. This can be hard to tell until the backer board goes in. I noticed this one was pointed down and leaning to the right. I put a tiny plastic shim in the top right corner to push it to the left, then a piece of copper clad strapping (see in photo) around the top part to try and get it level. I didn't like the idea of putting force on the valve and tweaking the pipes but a master plumber assurred me it was safe since it would only move a tiny amount. After cranking down, little by little, with an impact driver, I got it just about dead on.


 

This photo shows the plastic fixture that should be flush with the finished wall



Here's my checklist for setting the rough-in valve. You only get one chance to set it right. After the tile is up, it's probably too late unless there is access from another wall.

Is it perpendicular to the wall and set at the correct depth?
Is it centered? If there is a stud in the way of dead center, move it!
Is it centered with the shower head and drain?
Are the pipes secured to the studs with copper tape so they're not loose?
Is the valve fastened to the studs via a cross brace?