My sons bought me a floor jack from Costco a few years ago. I used it to put my 3" lift on.
Also used heavy duty jack stands...
Yep, just jack up under the pumpkin and place jack stands under the frame rails. Lower the jack under the pumpkin and swap out the springs. You don't need a special jack. Hint: jack it up as high as it will go when you put the jack stands under the rails.
I buy all my floor jacks and jack stands at Harbor Freight. They have floor jacks with more than 20" of lift and stands of 3 tons = 16" ; 6 tons = 23" and 12 tons = 30" maximum height.
If there is a store near you, go online, get some coupons, save your self a few buck.
I have a set of the 6 ton stands that work vey well under the unibody when I have to drip the axles.