As per my topic, has anyone tried stacking the P1 printers?
Are you talking about direct contact with each printer?
If so, I can see problems with vibration between printers.
Sounds like a very bad idea.
Remember that a calibration is performed to measure the response of each printer to vibrations during printing so that input shaping can compensate.
With stacked printers you will be adding unpredictable vibrations to both printers.