That's sorta hard to answer. A refrig will only cool so many degrees below outside temp the hotter it is the longer it has to run to maintain temp also the reverse is true.
RV refrig. are different than household refrig. in that they absorb heat rather than produce cold.
Thank you for the info. I suppose it will be trial and error. As it is still cool here in WNY I suppose we will have to wait and see...if it ever warms up!