I use a cooler incubator also much like yours except I have full water bottles in the bottom to help stabalize the heat when the cooler is opened. I also have a small computer fan wired in the middle of the cooler to move the dead air around. works great I have my first clutch cooking right now due any day. Pastel to spider and mojave got my fingers crossed for bee's also.
Good luck...hope you get some Bees!
Lucifer Sam, Siam cat...
Always sitting by your side,
Always by your side...
That cat's something I can't explain...