I've had terrible experiences with tire shops doing front end alignments over the years. After having my 65' Pontiac aligned by a local tire shop, it wandered all over the place and followed every little groove. None of theose guys knew what they were doing. I took it back and asked them to max out the caster. They put it at the max of the specs but would not go and further, said they are not allowed to go beyond the specs. It helped a little but still sucked...much like how you describe your truck. When I had to take my Bee in for an alignment, prior to go to a track day, I looked around for a front end specialty shop instead. I found an old alignment shop here in Reno called Sunshine Automotive. They had great reviews and after talking with them, I quickly realized they knew what they were doing. I talked about wanting more caster for my wide radial tires and they mentioned where my alignment should be for my application and going on a road course. They recommended going outside of the factory specs and they were spot on. My Bee drives great and honestly handles the track nicely. I need to take the Pontiac in to them to get it realigned. So, long story short, stay away from tire shops and find a specialty shop to do your alignment.

Good luck - Mike