Looking good man. You're pretty smooth at it right now. I would stick with whatever you feel is most comfortable and natural for you in the manipulation for the shotty and the ammo.
I agree with putting the dump pouch on your right side for the shotgun ammo, if you're going to be using your right hand to manipulate the ammo. With that said, though, if you're also going to have a pistol on your right side in SHTF for a back up, you may have to position the dump pouch in front of your pistol so it won't get in the way.
Keep up the good work, and I'd love one day to start working on a tactical shotty training for myself one day, as its really sweet, and certainly has its tactical place. Right now, I'm only working on rifles, but I may take up this mantle one day and train with it.
Overall it looks good man, just keep practicing what you're doing man.