Quote Originally Posted by JMugs View Post
I ran a small oven that held six mugs for a while (9 would have been possible), so not quite the same scale. My studio was always cold in the winter so I used a second oven set at 40 degrees to preheat mugs, my random failures became very few. Bonus was I stopped making adjustments from winter to summer.
This would illiminate the cold spots issue.

Janners
Can I ask how long you pre heated the mugs for?