I wonder if M&R may not even have a unit that they would rent out, similar to the box of valve shims many dealers loan to home mechanics, charging only for those used.
btw, brownbear, if and when you do get the jig, I sincerely hope that rather than needing to adjust it badly, you, in fact need badly to adjust it. Anything worth doing, is worth doing well! LOL!
Otherwise, I do have a name of someone who may well adjust it badly for you.