The Hi-lift jack is a great off-road tool, as you may already know, it can be used as a winch, can be used to unseat tires from rims, and of course lifting things up.
There are some safety factors I think the owners manulas might not cover though (can't say for sure, it's been a few decades since I've read mine!) Whenever i have to use my hi-lift, I always: ensure it has secure footing. Wouldn't do me or my jeep any good to have it "kick out cuz that damn rock rolled out from under it" No No.
While performing tha actual lifting of any vehicle, MAKE SURE OPPOSITE END IS CHOCKED! (Depending on terrain, chocking may not be required) parking brake will help also. What I've discovered (one time the hard way) is that when I'm lifting and lowereing a vehicle, it is very important to NOT remove your hand from the jack handle while a load is still on the jack! If your hand slips off for any reason, or is removed, that handle will not stop flopping up and down (with force)until it's beat you sensless, and the load is on the ground! That could be a while if the load was lifted way up!
Lift the vehicle only as high as necessary to complete whats needed. There are a few more suggestions, but I've run out of time.......