So any thoughts, advice or warnings regarding the 57 lb kicker motor?
If the question refers to transferring the kicker from your Mac to the dinghy, don't do it. If you do, once you get it on the transom of the dinghy, leave it there I disagree with Jimmy's evaluation.
That motor is far too heavy to lift with control. By that, I mean to be able to lift from a higher platform to a lower one, sustain holding it while trying to align the fastening clamps, all the while sitting/standing on an unstable floating platform.
My 6hp Mercury 4 stroke weighs 55lbs, and I will only mount it on my Achilles inflatable while attached to a dock. If I was to need to tow it, I would do that with the motor attached. I recognize that presents a danger in the Merc. getting damaged if the dinghy flips, but the motor is not going to the bottom, which is probable if trying to lift from the Mac to the dinghy, or vice versa. Far too risky for something that heavy.
I stated this in another thread about the relatively same question. Even though I'm seventy-one, I worked over forty years in furniture delivery, still lift weights, and would not consider lifting that awkward a weight in such unstable conditions..