Thanks for clarification on the I650 Stearns® VR™ Versatile Rescue vest. Looking at the webbing it seemed like it should be able to take a hoist especially with the Optional Auxiliary Tether System which attaches to either shoulder. The "Supports up to 1,100 lb. when properly integrated. . ." makes it seem ready for a helo hoist.

As I recall from the helo hoists I've done, all the weight was taken by that wide piece of webbing across the chest and the leg straps didn't do much. As you said, the leg straps just keep the vest from riding over your head.