I wanted to update my experience with my Chill Gorilla. Last month it saw its first real hard rain test, 12 hours in the Smoky Mountains. I noticed after about 3 hours moisture clinging to the inside of the tarp. It did not appear to be coming from the seam. So either it was condensation or bleeding through the fabric.
In any case the droplets clung to the inside and rolled down to the ground letting me stay dry that night.
So I'm confident with the tarp in scattered showers but that desire to upgrade is more pressing than it was before.