This design works great to get at the top of the screw adjusting the Z zero point, but that wasn't our problem. We have the locking nut also on top of the Z plate, and it's quite difficult to get at that to unlock the screw. This funny-looking bent open-socket wrench slides over the nut without bumping into anything, as shown in the photo. Once unlocked, you can spin the screw to the desired height with your fingers -- then use the wrench to lock it again. Really quick Z adjustment!