Well I'm not sure which fix did it, but I stopped the leak. I put a flat washer and a copper washer on the wingbolt outside the filter, and a fat rubber o-ring on the inside of the lid. No leaks from the filter on the next priming run!!
Unfortunately, the swivel adapters that came with the oil lines BOTH leak, but this seems like a simpler fix - replacements on the way.
Thanks everyone!
