Well.. I am not sure about the CA under temperature will not last... Maybe I was wrong.
But Stanley, Myself and some others had already had it on for quite sometime now. No problem.. YET... Stanley had it in his Rally/track machine and mine for 'parking under hot sun' haha..
The foam side up with the glue, I don think water can penetrate to get into the foam. Maybe only the side which will dry up lke you said.
The reason why I stick the foam side up as I stated for the hood is so that it is easier to clean. My engine is 21 years old, oil, water and dust will get sprayed up to the hood. With the smooth side down. I just need to wipe it clean compare to washing with brush and all last time.
At the same time, The foam can help me prevent my hood from vibrating that much.