I've wondered about this, too. I also have an Outsak, but I've wondered if I might be able to leave it at home and just hang the food bag from a slippery, small-diameter string in areas where ravens and magpies are not a problem. I looked into a lot of different kinds of string for this purpose, and ended up buying some BCY 450 Plus Dyneema/Vectran bowstring. It has a nominal breaking strength of 155 lbs, it is very thin (about 0.2-0.3 mm), and it has a slick, waxy surface. I plan to use it as a "leader", only for the last 2 feet or so of line where it attaches to the bag.
I've done one climbability test in my backyard. I have a bird feeder that is frequently raided by squirrels. They climb down the twine it hangs from. So, I got another bird feeder of the same design and hung them both from the same tree branch. The birdseed disappeared from the one hanging from jute twine, but not from the other. I switched the birdfeeders and repeated the test and again the one hanging from the bowstring was not raided. I even observed a squirrel attempting to climb down the bowstring and giving up.
I don't know if the bowstring would also frustrate mice, and I don't know if it will survive repeated abrasion against branches.