The harbor Freight under hoist safety stand are rated 2 tons. I can't find anything in print, for these of any similar stands from other brands, that say if that's 2 tons for a pair or each. A guy on the HF customer service phone line spent some time looking and said the rating is for a pair.
I'm working on a Chevy trailblazer on a 4 post lift. It is difficult to find places to safely lift the wheels off the ramps. Most of the frame is over too close to the edge of the ramps to use any jack or stand on the ramps. I'm trying to adjust alignment so I can't lift under the control arms, they have to be free to move when adjustments are made. There are no places where small contact point for bottle jacks, doesn't look like it could slip off. A piece of wood between the bottle jack and the frame is easily crushed by that small contact point. I can put a small trolly jack on the jack tray, but that doesn't leave space for jack stands. To leave the lower control arms free, the only place for jack stands is also on the jack tray. I can use 2 screw type 2 ton scissors jacks on the jack tray and get 2 jack stands. It still doesn't feel safe. The scissors jacks are a lot of work.
As I write this, I ask myself why do I think I need to lift the whole front end to make adjustments.
To replace front suspension parts I lifted one side at a time and it was supported be a jack stand on the jack tray, the tall safety stand from the floor, and the jack that lifted it, and I really wasn't under it when the tire & wheel was off. I like 3 supports if I'm gonna get under something. Most of the part changing work was not from under it.
I think the front curb weight of the Trailblazer is about 2600 lbs. That's the weight under the tires. A convenient frame contact point for the safety stand is further back and would pick up a higher share of the curb weight.
SO, the question is: Can 2 HF safety stands support the whole front end of my Trailblazer? If I can remove the jack I can also put 2 jack stands on the jack tray.
What do you think of lowering the lift a little with the safety stands under the front? I don't think I want to try it.
All this because I don't have any faith that an alignment shop will actually do the work.
On the trailblazer, camber and caster is set by loosening 3 big bolts and pushing the lower control arm bracket around with a crowbar. It's a tedious process.