If I had a non-tag coach and noticed a front alignment problem, either I would get new tires for the front or take a dually set and make those tires the 'new' front tires and put the 'ever-so-slightly' worn front tires in that dually position.
On our previous coach, I did get a bad alignment from Colton Truck in Colton, CA. I didn't catch it until Nashville, TN. I was getting severe wear on the inside of both fronts. So, an excellent shop in Nashville, TAFA (Tire, Axle, Frame and Alignment) put us back together like new!
I rotated the worn front tires to my my tag axle tires and we were ready to roll. That was the most perfect alignment I ever got and it lasted for several years until it was time to replace with a new set of tires. I received $50 each for my 7.5 yr. old take-off's. (tire dates 2006-4306) in May of 2013.
On my new coach, my front and tag tires are 365's... the drive tires are 315's, so I could still use the same method as before by switching the tag to front, etc.
That's my story.
MM.