Range of OK live Z values.
I'm using a square, 1 layer high to set live Z. I find it works over a range which surprises me. I find good results over (at least) a range from 0.000 to 0.020
I don't currently have any way to check actual layer height.
I realize it's just a matter of opinion and there are a whole bunch of variables but over what sort of range would you concider "close enough"?
RE: Range of OK live Z values.
0.000 to 0.020? That sounds a little too high ... if you have PINDA or MINDA properly installed and height set with credit card or tip of the ziptie, you should be somewhere around -0.7 to -1.3 mm. Probe triggers at 2 mm, what you are doing is lowering the nozzle down to almost touch the surface, thus negative height. Check this video if you haven't seen it as part of assembly: at around 8:40