There is no gauge for this pattern as it is a very flexible pattern which you can use a wide variety of yarns for. The Feza yarn is made up of 10 or 11 different yarns, all different thicknesses and using a larger needle and the lacy pattern makes it all flow beautifully.
If you knitted the Feza in garter stitch it would come out all different widths due to the different thicknesses of the yarns used.
This is also an excellent stashbuster pattern! Why not choose yarns out of your stash and make one, it looks really good with a textured/fluffy yarn at each end.
Pattern is available in PDF: Feza scarf pattern