Good deal to have a hoist.
Make sure that thing stays up in the air! We have 400-500 hoists and hoist systems at work, and they are considered one of our greatest liabilities (insurance/OSHA wise).
Sounds as though you are quite familiar with this type of thing since your talking about insurance and OSHA.
What's your opinion of this setup???
2x6's bolted with 1/4x5 lag bolts with flat washers at 4 corners and spaced at 2 feet into the bottom of the truss frames. All holes pilot drilled to avoid splitting. I'm certain I found the center of each truss 2 by 4.
Rail bolted with 5/16x3 lags with flat washers. 3 bolts at each 2x6. Rail sections are 8 feet.