Geoff,
I'm not a physician, but I consider a high dose 400 to 800 mg. 1000 mg is a really high dose. Before the Vioxx controversy, many physicians would have prescribed a COX-2 inhibitor becuase of the risk for GI bleeding.
You could always call your physician and ask. I'd suspect that he or she will say a proton pump inhibitor couldn't hurt. Plus, they're inexpensive, so there's not much financial impact if you get an OTC version. If you do go this route, don't bother with a prescription PPI unless your copay is lower than the cost of OTC.
I'd be curious to know what your physician says.