DLP Z-compensation Calibration part

Hey everyone,im struggling with the development of a new calibration part for my DLP printer. As seen in the attachments im currently using a hollow cube as a calibration part where i cover influences in X- and Y-direction. As it is square, i still know that i´ve got inaccuracy due to pixel rounding effects and i strive for a circular cal. part. What else i still want to cover with a new cal. part is the influences in Z-direction. It is clear that there is the Z-shrinkage and the Z-compensation. The compensation describes energy penetration effects only relevant to downskin areas. I attached pictures with visualised effects for Z-shrinkage and Z-compensation.Does anyone have a clue how to compensate these Z-effects in a calibration part? I thought about a window in a circular cube that can get measured and compensated.Thanks for your help and enjoy ya day.Michael