I'm curious if it worked for you? I also have a 3 year old mosquito-magnet, and the Repel (lemon eucalyptus) worked GREAT! I don't put it on his face or back of his hands, because of all the warnings about it getting into the eyes. I put it on his neck, ears and under his chin (as well as any other exposed body part), and it has worked great!
Unfortunately, the bug band did not work as well for us. Repel is easily available in stores, we're going with this for now. The only complaint is the lemon smell is SO incredibly strong, that we have to wash it off when we come back inside. It is a pain to spray him with bug spray to just go outside for a few minutes, to then face the bath-struggle when we come back inside.