Yeah, I found about the same amount of success using either the knife or skillet.
pro-tip: Use your low level fish when you first begin using your cooking skill to make sand (ie crawfish). The success rate is much much higher compared to other fish. Basically if you aren't getting good success, change to a different fish (preferably what you were catching most often when you were a fisherman rank 1-6). I had like a 99% success rate using crawfish. By the time I used up a stack and a half of crawfish I was cooking rank 4, so my other fish in my inv. were a lot easier to turn into sand.
*Retired :: August 2002 - December 2005*
Linkshells: DigitalBackSpin, DBSDynamis, CKofVD
Goldsmith 85, Blacksmith 30