Hi Krista, Well the things that I responded to in your post were the straining at stool and urination and well as the difficulty in walking - which is why I suggested Alumina to have a look at in an older cat. I don't know what symptom combination you saw but if it was like the ones I noted then if it was me I would look for improvement in those areas, urination, stool, eating, gait. If there is some improvement, then a slowing or a relapse, I would consider repeating a dose of the same remedy by placing your 30C in a 4 oz bottle (just like an LM) and administering divided doses accordingly.
However, if those symptoms have ameliorated and other characteristic symptoms in the overall case are predominant and/or life threatoning then yes, you need to look at an allied remedy based on the symptoms. What are the symptoms you are looking at that indicate the allied remedies you have mentioned?