Best protractor for aligning to cantilever

So who can etch something (and drill a hole in) a piece of glass mirror for us? Let's make a 12" round mirror and use the space to really make something useful. :)

Well I got a Wallytractor,on loan from Jeff Catalano of High Water Sound.Got it in two days,and offered to buy it from him,as I want to re set up my newly arrived Phantom using other means for comparative purposes.The supplied jig is good,but I am getting fanatical these days.Tired of fotzing around too!!!-:)
Jeff mentioned he could get these readily,as he is friends with Wally!Some who have had bad experiences ordering these may want to give him a call.
From just looking at the Wally I will say that it seems to "really" cover the spectrum of set-up issues quite well.
My ONLY complaint is that one would have to be in really good GYM shape,what with all the body contortions necessary for exactitude,and re-checking azimuth etc.
Fortunately,I hit Ballys four times a week,but I have a sneaky suspicion that I will be exhausted tomorrow,at this time!-:)
Best.

Wally answered the phone yesterday and assured me that my order is going to be shipped. He also apologised for the delay and is including a 10% refund with my order.

Sirspeedy I'm like you getting a little fanatical my self. Since Tri Planar arrived the improvement in sound is nothing short of phenomenal. I want to be absolutely sure my arm adjustments are 100% correct.

Stltrains,I'm really happy for you!!!DON'T get too fanatical though.-:)
I just got my new Phantom,and spent all of last Saturday setting parameters.Listened Sunday,and fine tuned.....
Broke down the set-up yesterday(what a pain in the tush)and re-set parameters,since I had tightened up the play in the Graham jig,to a tighter tolerance(it is now perfect).I couldn't live with the thought of setting up everything with a little play in the jig,knowing I had tightened it up,and could do better.Went to dinner,and watched the boring Heavyweight fight on HBO...I would have played around some more(last night)but the wine said "no"!
Just finished another 1 1/2 hrs re-setting everything,and will listen,and tune some more this afternoon,when I will do some comparisons between the Wallytractor and the Graham set up tools....WHEW!!!!!!
I believe the Graham jig is now dead perfect,and am very confident I got pivot to spindle distance,and stylus overhang "spot on"!...But us being fanatical(rubbed off from other Audiogoners,I suppose)is valid with regards to the money spent(alot),and the potential performance from LP!
I have a suspicion the WALLY will be very helpful with azimuth,in my afternoon session,today.After that I think I'll be collapsing from exhaustion!!!!
Now I know why some friends of mine use additional set up guys.I,myself like to do stuff on my own,but my back is paying the price.-:)

I am rediscovering vinyl and wish to set up my (Micro Seiki) arms correctly, but am only familiar with the basics. I'm not even sure what a protractor is supposed to do, or what the subject means. I would appreciate suggestions on how to proceed. Cost is a consideration.