I’ve run cylinder head temperature on World Formula engines in the past, but I don’t think it’s necessary. For LO206 probably even less necessary. You don’t have to worry about head temps like on a Yamaha. Just RPM and the correct lap beacon for the track.
IMO – The most accurate sensor for recording lap times is your transponder. You should be able to fit a magnetic or RF sensor to the M5 for lap times. But the all the AiM lap time sensors have their faults. Use the GPS on the M5 and don’t be concerned about the other lap sensors. I was a GPS skeptic, not any more.