I'm about to embark on this journey myself. My Triumphs' wheels are really bad, but the splines are still serviceable, so I'm going to try my hand at truing them myself. I have just about gone all the way around my "practice" wheel(my spare) and freed up the adjusters and replaced any broken ,rusted,and damaged peices. now I'm waiting to start work on the front suspension so I'll wind up with an extra hub and spindle. I plan on turning it into a jig to spin the rims on while checking them with a dial guage for runout. I've even given thought to expanding on the "tuning" idea of hitting the spokes to compare the tones,by using a clip on guitar tuner. But I think that may be getting too critical. I'm fast finding out why there aren't many places that do this. It's VERY labor intense. I've spent more than two solid hours just freeing up the adjusters on the first wheel and I'm not completely done yet! Then I have to true it up,sand blast it, and paint it. It makes the new wheels look like a good deal (they definatly are in the case of the 13,14,and 15" sizes) But I'm broke, and I'm the kind of person that wants to do this just to see if I can ,did I mention I'm broke.
If you do buy new wheels then keep in mind that it is STRONGLY advised to replace the adapters on the car, as the worn splines on the adapters will rapidly wear out the new splines on the wheels. This is where Triumph guys have an edge on MG guys as the TR adapters are bolt-on and not an integral part of the hubs and axles.
So if anyone out there in the upstate N.Y. area has an extra worn out60 spoke 15" wheel to get rid of as a doner for parts I have a home for it