When I first got my hi-lift I practiced in the driveway. The Jeep fell of the hi-lift, or almost did and I stopped before it did, but basically, you can't use these to lift a vehicle by the frame or bumper to change a tire. One of the problems is that our suspensions flex and the vehicle lifts but the tire stays on the ground. I've seen people "solve" this by putting limit straps on and I've seen these straps break in the field while being used.
But I still use mine, but safely. I use the lift mate to lift the flat tire then slip a jack stand under the axle tube. Then I lower the flat tire onto the jack stand. Change the tire, lift it again, and you're done.
Twice the lifting but way safer. I also carry a bottle jack for when that works out, that's even better. But I use the jack stand.
This is the slow way to change a tire, but the safe way in my book. (And since getting at my spare tire is at least a 30-45 minute job, I'm in no hurry...)