Imho (and sure it's different for each cat) the pill steroids make them feel a little better than the jab does - that's really strong and will zap any inflammation that is causing Shui's problems. I so hope he's better soon.
the pill steroids would be a course btw. You can't stop and start them just like that but have to wean them off. The best dose = the lowest dose at which they are effective. All I'd say from our experience here is try if possible to give them at night. The NOAH compendium recommends that. I couldn't and didn't just give them at night and I think if a cat takes them long term (which may not be necessary for Shui of course) that the NOAH people are right in that it can badly affect the cat's ability to manage stress. (the vet doesn't totally agree so there is a diff of opinion).
I'd love the name of the natural remedy when you can. If you can't remember what the vet said and you are worried, I'd just ring up and ask to speak to them and take notes - I have to do that all the time as forget everything otherwise.