Adjust your z-offset first, after M500. I don't use the z-offset wizard, I just put the hotend in the middle of the bed, issue G1 Z0 to bring the bed up until the IR sensor is triggered, then increase the height of the bed in 1mm and 0.1 mm increments (counting how far up it goes) until my feeler gauge fits just under the nozzle (feeler gauge thickness is 0.102 mm). Once I know this number (in my case it was 6.10 mm), I issue M206 Z6.10 to set the offset. I heat the hotend up as well, before G29 P1. Not necessarily all the way, but close. So, if I'm going to print with ABS, I'll heat the hotend up to 200 C, and the bed to 80 C, then issue G29 P1.