Changing the springs from on top to below the axel will lower it more than a little. It will lower it the thickness of the axel plus spring. Around 5".

You will have to make a new plate to weld to the bottom of the axel. You probably should remove some of the springs to soften the ride. I have not done this(I always go w/a IFS),but there is noting wrong w/your approach. Hopefully some one that has done this will step forward.