I have only used the basic z height gauge that came with my chinese router a few years ago, but have been looking at a better alternative.
Not sure I have found it yet, but I am looking at how Avid CNC ( Formerly cncrouterparts.com ) impliment XYZ zeroing..
I will use their amch 3 code but make the touch probe myself.
That might be usefull to you?
I'm going to make it in 2 parts, a top and bottom sectionand they will 'lock in alignment'. Bottom will be plastic with 2 raised sides for edge finding and the top will be Ali with a 4-5 mm pocket milled in it. ( hard to explain here and I don't have a pic atm. )
https://www.youtube.com/watch?v=0CWe3VP8ZCU

Steve