Don't understand what a D-Fly unit is or does. We could get a fully featured Garmin unit but right now, I'm really only interested in gear position (front & rear) and maybe battery life. The other things that I might be interested in are current speed, distance, average speed and maybe max speed. The other stuff that fully featured devices offer, I'm not really interested in. I'm not one to download & keep track of rides.

Our bike is not coupled.

Also, I will check what you suggest about the pick-up pins. Maybe that is what is making the noise. In that event, the precise location of the front derailleur won't matter.

I don't recall what cranks & rings we have. I will look tonight. Is it possible that the big ring might need to be moved slightly outboard?

Thanks