Anybody ever use TouchDRO? I upgraded my little mill 6 months ago, and I just finished upgrading my lathe to both use it. It's spectacular. You need an old Android tablet and the little TouchDRO box, plus your choice of scales off a few of the cheap Chinese DRO upgrades. Some guy on the internet is just making these things out of his basement and sending them out in little 3D printed boxes, but they work awesome and blow the doors off a conventional DRO.
I have the one on my mill set up to add z and quill, so it just gives you total z height no matter which control you grab onto. It gives realtime chipload if you have a steady enough hand for that to be useful, which I do not. And it does REALTIME VISUALIZATION of layouts. You can set a bunch of points to do some sort of layout, such as a flange, and it will give you a realtime diagram of the workpiece and tool position and just auto-zero on the next closest point. All you have to do is go to 0,0 and you're on centre. Totally crazy.
Quick layout of holes for a flange. That screen moves around and updates in realtime as you move x and y. CRAZY!
For my next project I'm going to add a scale to the tailstock on my lathe.