I used a 12 gauge with my old Cookshack because that is what I had laying around. Worked well; no problems. Haven't needed one with the 3D because the cord is longer. And welcome to the forum.
I use a 12 gauge, 3 wire cord, but length of your cord will determine the size. Anything over 50' should be 12/3, in my opinion. I've ran my 2D and 3D successfully with 100' 12/3.