Can't help on the sizing, but I rarely if ever buy anything sight unseen. I'd suggest going downtown, approach the front door of a sewing/fabric store, look up and down the street, and if no one is looking, step in. One can find all sorts of fly tying materials at 1/3 the price charged for sample size pieces in most fly shops. I always insist the clerks not tell anyone I was there.
Good luck out there
+1......
