Shark Bait your cert 4 will be such a big help mate. I to have my cert 4 and I will be doing similar to you in a few years.
The benefits of a cert 4, that no kiting instructor could tell you is that you know how to plan a session using the tools and knowledge you gained from extensive training. e.g plans, adult learning principles, feedback, reward the list goes on. The main thing is, to do your cert4 means you enjoy teaching and would not be doing it solely for money. Only partially.
In regards to having experience, well if your at the level you state, that's better than the our local instructor since I've learnt I've never seen him out. Hang on, yes I did he was running back up the foreshore footpath with all his gear in his arms because he f###ed up some lines and ended 2ks down the beach.
I say do the IKO and go for it you know all the safety, flying and getting them to stand up instructions so why not. If anyone ever tells me that you have to be able to do a back mob to be an instructor I will smack them fair square in the head.
Instructing does take knowledge but only of what you are teach. Most importantly it takes patience, persistence understanding and a safety conscience person. Reason being they are new and may not aware of the hazards
My 10c worth