Hey Karen, if you are still having trouble finding a supplier for the stickers, I may be able to help. We get our helmet stickers in Canada. You send them a hi-res pic and they send you a proof and then you pay for the quantity you want. Not cheap but they will last around 10 years!!
We get 50 pair (left and right facing) for about $80au landed. That is three colours and re-usable!! they are about 2 mm thick though, but I'm sure they can do anything you want. I will email my guy over there and ask.