Tri planar and shelter 901 and Verdier

you can obtain very accurate rulers and protracters from your local drafting supply shop.

At this level I think professional installation might be the way to go.

Dan, I have installed an arm on my sota star and on my vpi aries 2. but both times the arm board was pre-drilled. While drilling a hole seems easy,even if done correctly it can look ugly. I never do anything myself unless I can afford to replace it if I screw up. My Sme IV slides back and forth on a a sled. So if you are off a little it's okay.

When dealing with components like these the measurements should be as tight as possible.

I agree that if you have reasonable handyman skills you should be okay. Take your time. As carpenters say measure twice cut once.

The tri planar remains at the top of wish list.