Our belief is that the 'core' problem of stone formation is a proteinaceous nidus that is formed from ongoing renal tubular injury. Since they are just epithelial cells, they can be replaced, and the animals don't often manifest azotemia. This generally occurs in response to an excessively processed diet.
To remedy the problem, we move towards fresh food (and hay) and start using renal anti-inflammatory formulas like San Ren Tang. I would say if you have lots of time (i.e. no obstructions or extreme discomfort), then maybe pursue that for a bit. The goal is to stop stones from forming rather than focus on their dissolution. My theory is that they are always dissolving steadily, and that when see them persist on radiographs on in the urine, we are actually looking at new stones and crystals
Steve