I do not suggest cotton for this pattern. The natural stretch and give of the lattice pattern takes into effect the working of wool, but cotton doesn’t have the same return spring factor. This is also knit with a lot less wool that you might expect - only 2.5 skeins of Noro Kureon, so you might want to splurge on some pretty wool yarn for this one! If you like you could even get by with 2 skeins, and shorten the number of pattern rows and the strap a little, as the pattern gives so much.