Explorer's vest blog post – sources for twill tape?

Hi, all - I've been on the lookout for very fine (lightweight? thin in the vertical direction) twill tape, and all of the twill tape in the 5/4/17 blog post got me thinking that I should ask a collection of people who are likely to know that sort of thing. I mostly want this for adding homemade labels to garments, so off-white or white is fine, but I'd strongly prefer 100% cotton, and again, as thin and flexible as possible. I'm looking for 1/2" to 3/4" widths. Any suggestions? My local stores only have the stuff that's fairly stiff.