Legrand Mosaic plate for Merten system M

"Merten system M" timer switch is compatible with "Legrand Mosaic" frame but not its plate: central part is not large enough.
Therefore the plate needs to be a custom design. Unless the one from Merten works for Legrand but I doubt.
This design can be a good start point for any Legrand Mosaic part.

Parts used:
Merten Timer Switch insert, 2-pole
Merten 567519 Central Panel for 120-Minute Timer Switch Knob
Legrand Mosaic LEG90591 Switch / Socket Frame for 2 Modules Depth 40 mm