My heart goes out to you. I would be the same as you, worrying about the choice I was making.
The only thing I can say is that if you go to UT, Dr. Tobias would most likely not be doing the surgery. It will be people trained by her or by her methods, I believe. You might want to look into that. There are surgeons all over the country who were trained at UT and/or by her. Perhaps she was the leader in LS and might have been the best option at some point, I am quite sure others are quite competent with this surgery. One very important thing is to make sure you only go to a board certified surgeon. They are listed at:
www.acvs.org
Going to UT would be an inconvenience for me, and while I would do that for any of my pups if it were the only option, I would definitely consider closer places.
Feedback from others is important....have they used the places closer to you? I would want to talk to others who have taken their pups for surgery...not people like me who have no experience with surgery for LS. I have been fortunate in not having an LS pup in all of the years, so I am not a resource for you. I can only say what I might be looking at.
As I just read the above, it occurred to me that you don't have a defnitive diagnosis. What I said above applies to that as well. You want someone who is skilled to evaluate for LS vs MVD.
You will be in my thoughts.
I wish you well. I know how it is to have sick pups and have to make decisions about surgery. While I have not had a pup with LS, I have had many with other conditions.