Finally something I might be able help with.
Are you talking about electic or the hand held ones? The big eleictic ones are pretty much one size grommet. Ether a #l about 1/4" diameter hole, #2 about 3/8" and so on. Theyuse the same grommets in both the hand held and the machine. If it was me I would go for the hand set for the cost and veriaty of sizes you could do.