You betcha man. Happy to answer your questions!
-The zippered side compartments on the bird bag itself are the 7" wide and 8" deep. The zipper runs across the top of the side panel. I can fit my hand in, opened up, pretty easy. I personally leave a first aid kit in on one side and usually toss my an extra camera battery, beanie, gloves, etc. in the other.
- The zippered back panel isn't intended for a bladder use. I'd hate for such a heavy object to be so far away from your body. There is a clip at the top of the two panels where a water bladder hangs, keeping that weight close to the body. The bottom of the bladder hangs in the pocket that runs horizontally across the back. That same horizontal pocket can also hold a 2L lumbar bladder. I'm not a big bladder guy myself, and usually put things in there that I need quick and easy access to, but don't want them to get covered in feathers and blood. That's the beauty of the design. You can use it however best fits your needs.
- For the bladder hose, I feed it up between the two panels, through the small carry handle on the shoulder straps and over my shoulder into the horizontal straps that sit on the shoulder straps (where you shoulder a gun). It keeps you from having to add extra clips, or gadgets just to keep a hose secure. Never had any issues with it sliding off or going askew.
Holler with anything else brother.