For setting a hybrid SM-MM transmission, a pair of PK-SM-MM converters always needs to be used in such a way that the MM fiber is in the middle, and both ends are single-mode (using a short SM patchcord from the light source to the connection with the MM cable is enough, if the link doesn’t have a natural SM-MM-SM configuration).
Maximal link length is limited by power budget and polarization mode dispersion of the multimode part. For 1 Gb/s transmission, the maximal length of the MM part is <400 m.