The fronts probably won't settle any. At least not in the near future. It's usually the rears that do the settling. Sorry to hear yours isn't sitting where you want it.
Of course it's "possible" that rolling it might free something up and let things equalize, but it doesn't sound like it's going to do that from here.
Only one way to find out though I guess, eh?
Yes, a 1" block would do the trick. But before you decide on that, if you're just using the old eyeball method of measurements, the best thing to do would be to lift the rear end with a jack until it sits where you like it. THEN measure the difference.
But even before you do that, make sure you don't torque down the rear spring and shackle bolts until the vehicle weight is on the ground, then drive it for a few miles to see if anything settles in the rear. Then measure the difference to see what you need to do.
And speaking of blocks, do you have enough thread left on the u-bolts to add some additional height to the mix? If not, you'll need to get longer ones.
Good luck
Paul