Hi,
the M3 in its normal form does not accept any trigger winder. It has to be converted to either the M6 drive or to the M2M/M4M drive (this is the one with the long take-up shaft. It is not a big deal to convert it to a M6 drive (DAG/Kinderman can do it). However, in this case I do would not recomend that you "flip" winders between cameras as the M3 converted cameras do require a slight modification to the drive, compared to a regular M6/MP winder. It will work on both, but you have to pick which one it is optimized for.