So in the not ideal of being in the shed, stacked on top of each other 8 high, and 8 more side by side under shelf, should pressure be reduced and to what amount?
This was the first year I had something that I never checked. I was putting the snows on the Pilot (Conti WinterContact Si) that were mounted on factory rims in November 2018. I took valve cap off to check air pressure and one was leaking air. I screwed cap back on and it stopped. I checked air pressure and it was the same as the other 3, down about 6psi. Took off cap and tapped the valve core needle a couple times, no change. Used my valve core tool and it was about 1/2 turn loose. I then removed/inspected cleaned and light coat of silicone grease on the seal and reinstalled it. I checked all the other tires 11 tires being swapped and all were tight.
I might buy some more of the Honda valve caps as it looks like they have a small O-ring in them to help seal. Not to rely on them, just an added thing.