I would agree to put jacks under the arms. If you are in a hurry!
If I were doing it I would put the jack stands under the Frame rail. Because while its apart and your changing the upper bushing. and upper and lower ball joints. why not install new lower control arm and strut rod bushings.
They are the cheapest and your going to need an alignment when you are done anyway. Ride height is part of the alignment. Once you have everything off for the swap. All that is left is the lower arms and the rods. Why not paint em up nice while your at it.
This is just the way us old guys do things. No hurry ,And one thing always leads to another. Before you know it the K-member will be coming out for paint and while thats out you could paint the bottom of the engine after you put a new oil pan gasket on.
PUT THE JACKS UNDER THE FRAME RIGHT FROM THE START, They also won't be in your way to keep the area clean. You'll be thanking me for the tip. LOL Steve