In the old days (pre bear canister) we used black or dark green parachute cord. However, it depends a lot on how much food weight you are hoisting up in the two bags. For group trips, we would often have 25 pounds or more of food.
The A cord is the dark one, and the B cord can be any color or white.
There are some very fine spectra cords. However, they are very strong and very small in diameter, and if you run one back and forth over a tree limb much, it tears up the bark and gets the cord stuck in the bark. This is not good.
On the other extreme, parachute cords are not as tough, but they are easier for an animal to chew.
In today's market, there are some cords with a spectra core, but with a softer braid over the outside. Some of these are pretty slippery, and that can be good or it can be bad.
Sometimes a tough cord gets used as a stream-crossing rope, so it is not stupid to have one strong enough to support one or two bodies. I like to use a cord with a 300-pound test strength.
Since I now use a bear canister, I don't need a rope for a bear hang, so I need only a stream-crossing rope (100 feet of orange dyneema).
–B.G.–