I like the Idea of an official "sticker" with the info of the diver from your site. It is simple efficent and not messy. I dive with dive operations who used to use stamps (which bleed when wet) and now use stickers which I think work very well. If you have several ideas for your stickers and have samples you might want to have some of us look at before the final sticker I would be more then happy to give imput.
Haz