i did a camp over christmas in gympie and it was damn hot
using the cfx 50 as a freezer
no insulated cover (yet but see one for sale here might soon be mine)
in direct sunlight from 6am to 9am ish then just hot all day
set to -10 and kept all frozen and also froze stuff that we put in including the kids 600mm water bottles over night
as we were only camping for a few day i did want stuff to be frozen but did not care if it defrosted
as it was all to be used before we left
when in transit on the back of the ute and also at home before we went i have it set to as low as it will go (-22)
all packed all frozen
when away for longer periods i might keep this -18 in mind but as the days start to run out bring it back to fridge temps
as i said above i don't want to take food home so don't mind if it has fully defrosted by the last meal its should still be fresh
Adam