Using 11-15mm M42 helicoid, its MFD is 0.47m.

From the left, M42->E adapter (1.5mm thick), M42-M42 11~15mm helicoid,
L39->M42 ring, and the lens. This is @infinity position for E-mount camera.

D in the above is about 23mm for E-mount case, so any helicoid less than
about 16mm (its base thickness) will work well. Although L39 ring is 3mm
thick, so only 20mm is available (in safe side), or you can use thinner L39.