For better airflow they should be on their sides. Air blowing horizontally.
For the original sales photo ops they look cool upright but should be sideways in operation.
I tell you what I am running close to 47 across the board on my six will side turn them and get back.
Okay my garage is attached to my house the car is pretty new so I keep the door to the house open this allows some ac to go into the garage
so :
it is 91 f outside my home
it is 85 f in my garage
the six pieces were 48C 49c or 50c facing up with room between them and above them.
I side turned them and in under 5 minutes they all dropped 2-3 c
All my units are now side mounted like I did with my 5 chip gridseeds. it seems that side mount is better.