For a spring swap the jack stands need to be under the frame rails so that the axle can be moved down to remove the springs. I put mine just aft of the front axle, where the frame is level. For the rotors, you can just jack up the front axle from the diff or axle tube and place the stands under the axle itself.
This would be if you are doing it on a hard surface such as concrete or asfault.
Chock the tire diagonally from the wheel you are jacking up. So if you are jacking up the DS front then chock the PS rear.
I jack up the axle near the gusset for the T/L arms.
Place jack stand under frame on the inside of the gusset for the T/L arms.
Lower jack until frame is supported by jack stand.
Finish lowering jack, remove jack
Proceed to next tire.
FYI, a gusset is a metal bracket that is attached by welding or rivots to a part and used as an attachment point. The gusset of the axle is either a left or right one and allows to attachment of either the Trailing arms or leading arms. The frame gusset is mounted on the frame to attach the other ends of those arms.
I put the floor jack just to the side of the diff, on the flat part of the axle. It'll lift one side a little bit higher than the other, but both tires will come off eventually. Then put a jack stand on each side of the axle and lower slowly.
What I do is drive the front up on ramps and jack up the rear and use stands.
Then if you need to do the front you just jack it up a bit and put stands under it.
What you DON"T want to do is get in a hurry and forget to remove the rear stands and drive the 80 off the ramps. This is why I have a Downey Cable Locker. THe actuator is not strong enough to hold the weight of the vehicle. I don't know if the skid plate for the actuator would of helped or not.
Thanks for bringing up this subject and triggering my memoryD)