I found a lot of posts asking, but no definitive answers - and nothing was added to the Aura Settings spreadsheet so,
I had a need to cut some cardboard in my Spark and found that 25 speed and 10 power did a beautiful job on a shipping box with no masking. Cut through both sides cleanly, no flashback, and no hangers on 
That’s great to know! Thanks for sharing your info!
Interesting that it’s not a preset if the machine is capable of it.
I know it’s not proofgrade, but the original machines have plenty of presets for non-proofgrade materials.
Me too! A bunch of responses on here seem to indicate it is/was, but I searched and it didn’t come up so I punted 