On which gimbal of the M300 RTK can the L1 be mounted?
The L1 can be mounted on the right downward gimbal port (when facing the drone) only.
Related Questions
What is the DJI Osmo Motorcycle Heavy-Duty Mount compatible with?
It's only compatible with the Osmo 360.
What is the controllable range of Zenmuse V1 when mounted on Matrice 400?
The controllable range depends on which connector it is attached to.
What mounting options does DJI Matrice 400 support?
The M400 supports mounting payloads via the single downward, dual downward, and third gimbal connectors.