I have had no issues and feel pretty comfortable at 10-12 psi.
When I add air I set them at 11 to 12 psi.
I sheared one valve stem this past winter, my own fault , it was -25 C, I did not check the tire pressures for about a month and the temperature dipped.
I checked the good tube and tire after, its pressure read around 4-5 psi, way too low as well.
12 psi on pavement should be no issue, 18 psi is pretty firm. I started around there too.
Kevin,
Kitfox Outback
912 ULS
Airmaster AP332CTFH-WWR70W
Summit Aircraft Wheel Skis
C-FOXW