The whole idea is this, that's all.

1(M42->E) + 14.8(Helicoid) + 2.1(StepUp) + 6(Mount) = 23.9mm
41.5(Miranda register?) - 18(Sony E mount register) = 23.5mm
The difference 0.4mm has to be grounded from the mount metal,
though not sure where the Miranda mount base is. So slowly grind it.

This helicoid is not glued, so it can be used for the other purposes.
(the helicoid is re-measured precisely: from 14.8mm to 26.4mm)