^^^ nailed it, that's the "sweet spot". I really don't want to recommend jacking this way for inexperienced users but this is how I do it too.

I would also like to address two things:

1) It is UNSAFE to use cinder blocks as jack stands. As mentioned, they crumble. Even when the holes are vertical, I wouldn't trust my life with them

2) it is also UNSAFE to work on your vehicle raised by only a jack. Yes, I'm a broken record! I don't want guys going out and jacking their jeeps up as seen above and thinking they can go yanking tires off. The weight is distributed but it's far from stable. Put some jack stands underneath the axle and lower it down whether it be on the tube or the control arm mounts. Don't put stands under the axle "C's" either. That's a big no-no.

 

Do you of the best part of the frame for jack stands when you need full droop?

 

If you need the axle to hang you can put stands behind the control arm mounts on the "frame" side. DO NOT use the pinch seam. It will just crush into the floor.

 

I see where someone has tried the pinch seem (not me, for once). Thanks for the info!

 

Another from Albuquerque here.

 

what is the pinch seam?

 

It's that thin piece of metal that's oriented vertically and runs along the bottom of the rocker panel all the way between the front and rear wheels.

 

The lip right next to the rock slider. That is the pinch seam. This one has a more metal bolted to it from the rock slider but you can't miss it when you go under there.

 

Whenever I had a vehicle I couldn't fit under I would just pull it up on ramps. Only time I really use a jack is if the wheels are coming off.

Still trying to figure out a way to set an xj on something while I have the coils removed. At 6" lift with 33's the frame is already quite high. I may have to try and find a set of giant jackstands.

 

I know your struggle. you could always build a set of small extensions for your jack stands to sit on out of 2x4's

 

I don't have much here you would call solid ground, much less a slab. I use my ramps like others might use jack-stands. With 4x6 and 2x6 blocks on the level part of the ramp, under the "frame" I feel pretty safe. Often I'll "manhandle" the Jeep, see if I can knock it off before I go underneath. On the lawn, or dirt, I might do that again after a rain or coming back the next day.