We havent figured out a way around the credit purchase limits, but what we can usually get by with swiping the same card twice, but a few years ago when gasoline was higher, when we needed to swipe three times, we would use two cards, one twice, and another card the third time.
I prefer swiping at the pump even if it means swiping two or three times, which I still believe is a lot quicker than going inside telling the clerk about how much you are going to pump, and then maybe have to leave a credit card with them, come back out and fuel up, go back inside to pay, and then come back out so they leave. This is one of my few pet peeves when it comes to RVing.