I used a few tools as well from the hyperspin days. don's list thing to get all the weird crap out, then some program that looked for the files that matched that xml in my mame directory and copied them out into another folder. Then i could delete everything (minus the bios stuff) that didn't get copied (didn't match the xml) and then re-copy the small set back into the mame directory. It was a merged set too, and haven't run into any troubles in I think 3 years now. But yeah, it definitely is a process. They really should break out all the mahjong, casino, etc., out into it's own set from the beginning.