Lab doggy door

Hey everybody I’m putting the finishing details on my new lab and my question is about the exhaust/air exit, my lab is 5’ wide 10’ long and 7’ tall, I have a 3’ x 4’ myers flowhood 1,000 cfm along the 5’ side that is backed into a prefilter room, so the flowhood is positively pressurizing, my question is where is best to put the doggy door exhaust hole, and how big to make it, here’s a pic for help I’m wondering back wall or side wall near the back corner and size 🙏