One side at a time can prove diffficult, as with the wheel on one side you may not be able to get the axle to drop low enough on the other side to remove the spring, as I recently found out when doing the 2 " lift on mine.
Things to bear in mind, make sure the vehicle is fully stable before and during, supported on the chassis by correctly weighted stands etc. Watch your brake hoses as you lower the axle, don't stretch them too far!!
In the end on mine I replaced them as an axle set, using a pair of 6 ton axle stands on the chassis, a high lift jack to do the lifting and a trolley jack to raise and lower the axle. I still left the wheel on the opposite side, I just had to make sure there was enough height to give enough drop on the axle.
SAFETY IS PARAMOUNT!!
Stef