RAM 2500/3500: measurement plz?

I am hoping that someone could give me a measurement for the height of the rear opening, measuring from the top of the bed rib to the top of the rear door opening? I have the DECKED drawers in my truck and I’m trying to determine if I’ll still be able to fit my large dog kennels into the bed with the platform camper installed.

It would be ideal if you’re measuring on a 5th Gen, but I think a 4th Gen should be pretty much the same measurements.