I was digging around at Cast Boolits, and found a thread on paper patching that included a piece on 'what papers may be better and worse' for various reasons. One of the 'could be very good' was coffee filter paper.
Well, I'd tried that once with a couple of filters from a coffee-drinking friend; cheap filters, didn't work worth a damn. Big problem was that after being wrapped and dried, it wouldn't hold in place, kept unrolling off the bullet. But the other day got hold of a couple of filters that seemed to be better quality, cut out some patches, and tried them. Much better result: the paper holds on much better. So now I need to lube and size them, load up a few, and- next time can get to the outdoor range- see if they shoot as well as those patched with onion skin.