I've been keeping a close eye on heat. There is 1 1/2" on the right, 2" on the left, 4" on the rear and the top is open(I removed the ceiling of the cabinet). We baked for an hour yesterday at 350 degrees with no issue. The door appears to get the hottest and air above the was unit was hot, but venting nicely.
I lined the cabinet with reflective firewall mat for some extra protection. I'll toss a temperature probe behind the unit the next time we do some extended baking. If it is a problem or for some additional safety
I've thought about adding some fans/vents and the rear of the shelf that can pull in air from the lower cabinet and vent it up and over the unit.