Lol, I remember how it feels the first time they're under the weather, all I can say is thank god my mum is a trained children's nurse or I'd have gone mad!!
The thing is to just try it out, if it works for him then great, if not, try differently next time. It's a bit rubbish but it's a case of trial and error till you find what works for your LO. I now know that DD responds better to nurofen for temps and calpol for aches and pains but it took a couple of goes to figure it out.
That's what's so hard about ill babies and children, there is no one right way, only what works for your specific baby + illness combination!