Finally started on my cab mods… 
I am converting it to flood and drain.
Pulled the back panel off, the white is the part that shows inside. (it’s upside down in the pic right now) and marked where I needed to cut out.
Shitty pic but I didn’t have room to get a proper picture. Here you see the tray part of the floor and the darkroom vents installed.
I’d say airflow has improved 10x 77F in the room, (admittedly up top of the cab where all the heat in the room is) And 71F in the middle of the cab!
Edit:
On payday I gotta get the “Big” vinyl tubing for the “Overflow” part on the flood and drain connector,
get some foam to put between the tub and the cab (where you see the sharpie line I drew)
then get one more “tough” tote so when I do res changes I can just move the lid to the already filled tub.
I still have drill the holes for the FND connectors as well. Reseal with caulking and paint fresh wood white for sealing purposes.
Things will be done this weekend.