Setting up your sling
Here is a pic of my old basement, I guess the ceilings were 7′. All the chains are 5′, and use the loop-back technique to eliminate dangle.
Try to fit your rig out with Snap Links, they are stronger than double-snap fasteners. Double Snap fasteners are cold forged alloy that can break under loads.
I recommend hooks set at 48 inches from side to side (3 ceiling joists) and about 7 feet from front to back. For any of the longer premium slings you can try up to 8′.
Try to make sure excess chain is not dangling from the sling corners!