For clarification purposes, I'll point out that Cotton Twill and Poly Viscose are 2 separate things. PV is not a 'universal' term for all non wool kilts... it is a specific fabric like Cotton, Acrylic, Cotton / Poly, Poly / Wool, etc...

***SIDE NOTE: 'Viscose' is the fancy British word for 'Rayon'***

Both Cotton and PV are 'not wool' but the makeup of either fabric is very different. Cotton is a 'natural fabric' and has different properties than PV. Poly Viscose is a man made fabric (65% poly / 35% viscose). SOME PV (the MM PV fabric) comes with a Teflon coating and has 'anti pill technology', while OTHER PV (woven in Asia) has a much looser weave and is NOT coated with Teflon.

You don't have to be quite as careful when ironing Cotton (it won't take on that 'shine' quite as easily if you iron it on too high of a setting), but it WILL wrinkle easier than poly fabrics. I would REALLY suggest sewing down the pleats about 1/32nd of an inch in from the edge of each pleat for ease of ironing. This will keep them 'in place' and make it MUCH easier to iron for touch ups or for after you wash it. If you do NOT do this, you will have to re-iron it every time you wash it and be careful to line the 'white stripe' up perectly every time.

Hope this info helps!