For what it's worth I use the top hat style grommets on the two piece machines and they seem to grip where you put them, and using needlerunners get a dead straight run no problem. The one piece has a different offset with not quite enough room for the top hat on the pin and allow a straight run, but I haven't noticed any snagging of the grommet. I can't fault them for any part of the tattooing process, it's just a case of learning how to work with it.