If you just use the hook dangling down directly, that's "single line" and has a 220# capacity. But you can put a pulley on the line and bring the hook back up to attach to the hoist, so you have a U shape. Because of the physics of pulleys, that cuts the raise speed in half, but doubles the capacity.
Did you get your channel brackets at one of the big box material stores?
What do you mean by "single line" and "double line"? You were referring to how fast the hoist would raise and lower
If you just use the hook dangling down directly, that's "single line" and has a 220# capacity. But you can put a pulley on the line and bring the hook back up to attach to the hoist, so you have a U shape. Because of the physics of pulleys, that cuts the raise speed in half, but doubles the capacity.