Love the photos of your fabie!!
What did you name him? He is gorgeous and I do love his cage. So much room, he should be in birdie heaven when he's in there snoozing.
I never used the diapers, not sure if it would mess his manners of not pooping on you up or not. Maybe you can train him to poop on paper when he is out with you and if it is carried with you he would still use it when he needed. I know they can be trained to let you know when they need to go back to their cage for pooping, so I would think he could be trained to let you know to let him poop on paper.