Recently I serged cotton jersey, 2 layers, with a 3 thread stitch and 2mm stitch length. I usually make note of the stitch width as well.
My notes looked like this, x representing the unused needle:
L R UL LL [left, right needles, upper looper, lower looper]
2 layer jersey, 3thr 2ℓ x 4 5½ 5 lower looper tight; upper looper wraps under
x 4 5½ 3½ upper very loose
x 4 6½ 3½ skips stitches
x 4 4 4 upper loose
x 4 5 4 Final setting
Next time I need to serge cotton jersey I'll save a great deal of time testing settings. Some tweaking is usually required, especially when changing stitch length or width, and that is also noted. I keep very close watch on these notes as you can imagine! Cotton jersey may work close to 4-4-4-4 base settings but muslin and poly satin have quite different characteristics. That's not even getting into rolled hems!