I find shorts with lots of pockets help a lot, and would never consider a bum bag. Proper shorts like, not some duff sports types, but the smarter ones with pockets on the sides.
That's what I use. Bought a pair while i was over there. It's amazing how much you can carry in the pockets of those shorts. Don't need to carry a bag at all.
Nick

We had a couple of "waist bags" on our first trip together but after much thought we decided NEVER AGAIN!!
.
the are quite reasonably priced too