This is a VERY old thread, and I do have experience, now.
1. There are different types of lasers, and the Vets use the ones that they prefer. I trusted my Vet, he was very conservative, AND I went to High School with him. When my 13yo Lab mix started having problems with his arthritis, we tried a few weeks of treatment. The first few treatments made a difference to make him more comfortable. However, after 3 mos, we stopped the laser treatment, b/c the cost didn't seem to justify the results, mobility was decreasing ... I can't tell if discomfort changed after we stopped. However, my Vet did tell me that sometimes it is a miracle, and sometimes it seems like snake oil ... you can't tell, and it depends on the the dog.
2. I never tried Acupuncture. So I have no opinion.
3. Whatever brand of Glucosamine that you use - I used Cosequin DS Plus, it will take about 30 days to get a loading dose. There is also an injectable that may help (you may be able to search the Forum or the Vet may know it). I don't think Glucosamine has side effects and that you can give double or triple doses w/o issues, if you think it is helping ... verify with your vet. It is expensive, and it doesn't always help.
4. We 'diagnosed' that my dog also had nerve degeneration. We didn't test, but based on observation that some of his symptoms and lack of mobility did not have associated pain, and his feet could flip under. Gabapentin helped with those symptoms, but it was a permanent prescription to reduce discomfort. A far as I know there was no way to stop nerve degeneration at that time.
5. Hydrotherapy may help.
6. If you know that your dog has arthritis, especially if he is a 100lb dog or is about 10yo, then he has probably been in pain for a few years ... That's just how they are. You can search the forum for various treatments, but a pain med similar to Rimadyl will help. There are many different types and options, and each Vet and each individual dog is going to be different. Nothing over the counter will provide the level of pain relief that meds will. In addition, I walked or let my dog hobble for 30 min. twice a day ... and he looked forward to that and for interactions with people ... I think the daily exercise helped significantly.
7. We titrated metacam, and it worked very well. But, liver numbers went up quickly. A young Vet suggested and stopped metacam, and an older Vet was not as concerned about the liver numbers for my specific dog. A short while later, we stopped the metacam when we diagnosed the nerve damage. I noticed more pain when we stopped.
8. I don't think my dog was suffering, but he was not comfortable when we finally euth'd him at 16yo. I don't think his pain was too bad, but the nerve degeneration decreased mobility, increased falling, and resulted in incontinence.
9. You can explore cetyl myristoleate ... some of the agility folks use it for younger dogs for joint issues. We tried it for a year, it takes a few months for a loading dose, and it helped at first, but eventually the benefits could not justify the cost.