Andy,
I have a spare mc18 cylinder which has been faced. I’ve seen a video on YouTube where T2Racing use a dial indicator fixed to a bracket which is secured to one of the head studs. Is this to check the piston height at TDC and make sure the correct thickness base gasket is used so that both piston heights are they same? Same squish on both cylinders ? Approximately 1.1~1.2mm ?