Hi mxcprod,
The L16 is a slightly larger version of the L12 with a bigger motor for faster speeds and heavier loads.
About the PLC/RC, it’s the type of control for the actuator.
If you look at the L12 datasheet, you can see the various configuration of available L12 actuators.
Search for “C:Controller” in the second page, the actuators we mark as “PLC/RC” use the configuration “I” in that page.
Integrated controller with Industrial and RC servo interfaces (see L12 Controller Options section). Not available with 10mm stroke length configurations.
We don’t know which actuator exactly you got. Which configuration and stroke but if you go with a lower gear ration (50:1 instead of 100:1) you will gain speed and also lose torque.
The L16 with 36:1 will sure give you faster response but there is no PLC/RC configuration so they can’t be use like RC Servos. L16 datasheet
For example:
L12 12V 100mm 100:1 - 12mm/s
L12 12V 100mm 50:1 - 23mm/s
L16 12V 100mm 35:1 - 32mm/s