We didn't try - I didn't want to deal with packing the bulk, or carrying that much extra around the parks. If you take FBs, I'd say to leave your hemp at home since it is so temperamental in different water harnesses (so your home washing routine may spell disaster at WDW). Go with the Wal-Mart microfiber towels or MOE microfiber inserts, or anything non-hemp. They will be more forgiving and will dry faster, and you can just get them super-clean when you get home to your own water and hot water tank!
Though I wonder if prefolds and covers would be more efficient for you, since you can reuse the covers?? Not as easy to change, though, and I personally am a disaster with prefolds...