Questions about "full service" gas stations re: ettiquette

Two questions about full-service gas stations:

1) Are you supposed to tip the dude who fills up your tank? If so, how much?

2) Is it weird to say that you can do it yourself?

I'm not used to full service gas stations: I usually hit the big ones and they're almost always self-serve. But I found out the other day that there's a station that's MUCH closer to me than others. The only problem: all the pumps are full service. And while I don't balk at the idea of forking over more money, I have social anxiety so something ambiguous like tipping makes me feel really weird and awkward.

ETA: Well if nothing else, at least notwI feel normal with my awkwardness <3