Had one on a cat, so can't advise on gimballing. The movement of a boat helps the coolant
circulation, or so I was told.
But follow manufacturers instructions completely. You need good air flow for the cooling
air. I improved the performance considerably by adding a 12v computer fan to aid in exhausting this air (I had already increased the vent area dramatically to meet the mfgs. requirement)
I was also told if performance was below par, to invert the unit for a day or so, to "burp" it. Seemed to help.
Note that (AFAIK) none of these things are really made for the marine environment
, so be prepared to fight rust.
Since the 12v charging
on this boat was an Outboard motor
, this frig was very satisfactory.