Reddit mentions of Wartenburg Stainless Steel Pinwheel

I actually really like the new Depends Protections. They are really soft and don't chafe my legs. Plus, they make a great doubler if you cut holes in them using a wartenburg pinwheel. Get one here http://www.amazon.com/North-Coast-Medical-Wartenburg-Stainless/dp/B0052ZW010/ref=as_sl_pc_qf_sp_asin_til?tag=simpthetrutfi-20&linkCode=w00&linkId=CUNSIUD4Y2KUMPEU&creativeASIN=B0052ZW010

If you want any use out of the second layer, then yes cut slits / holes / etc in the first one.

Here's the pinwheel tool /u/PaddedCthulhu was talking about

That depends on if you want to use both, or if you just want the outer one for the look/bulk.

Personally, I like to run a single slit down the entire length of the diaper, then put a couple of Abena stuffers inside it (one in front, one in back). This gives you a lot of flow-through, and the stuffers both add bulk/capacity and help keep the gel in. When taking it off, to avoid having the gel/crystals go everywhere, I only undo the top tapes, then pull down both diapers at once. Other methods I've seen suggested are numerous, shorter vertical slits, or making diagonal cuts in alternating directions.

One that seems to come highly recommended (although I haven't tried it myself) is using a pinwheel to make lots of tiny holes quickly, which is supposed to give lots of flow-through without any risk of spillage; if you're in the US you can get one for under $6, delivered.

Also, regardless of which method you use, it's best to stay away from the edges when making cuts/holes, since that's a recipe for leaks.