Good luck with that. Set your ride height keeping in mind the angles of the joints and adjust from there. Even on plates I never cranked the cams without relieving the stress on the cams. Not my car so have fun.
Good luck? There’s no luck involved. That’s the way it’s supposed to be done.
You can’t fully unload the cams without altering the alignment. So how do you set the alignment correctly? Turn the cam, lower the car, roll the wheels to put the car back at it’s true ride height, set it back up on your rack, then check what you did? Repeat a few dozen times?
Every professional alignment shop with an alignment rack makes those adjustments with weight on the suspension. You don’t unload the suspension to adjust the cams.
And again, how much load do you think is on the cams anyway? The lower control arms carry almost all the weight. The upper control arms just locate the top of the spindle, not hold up the car.