"Scientific diver at UC Berkeley under AAUS, which I also assisted in teaching."
Which basically says working, cold, kelp and surf. And leads to talking about what we cover in that class like NAUI rescue and master scuba diver and DAN first aid for professional divers. That, plus my BPW, mostly means I can hang off to the side and them not worry about me.
For a card, I give my SSI advanced that lists the complete classes I covered before that: Night, Nav, Boat, Deep, Search, Rescue and CPR.
I think solo is the top rec. card as it covers rescue but with no one else there to help you. With cavern and NAUI master scuba diver also on the shortlist.