It's a very good system, I tested thoroughly on my Kossel XL with "MarlinKimbra" firmware and I assure you that in a few minutes you have the Delta fully calibrated with a minimum dimensional error.
This system helped me a lot to find some precise measures for Repetier.
Also tune right my optical endstop offset.
Joined this would be useful to supplement the automatic storage of the ZProbe Z offset, here the command is "G30 X0 Y0 U1".