With belly bands you use an incontinence pad in them, which are aimed at adults not babies so would probably hold more urine. Not sure how a babies nappy would work anyway you'd need a hole for the tail. The belly band can be positioned over his anatomy too.

I used a belly band for a foster dog who would mark in the house. It worked really well for absorbing the small amounts of urine, and it stayed on just fine. I would recommend one for your situation, while you continue to work on training. It's obviously not going to solve the problem, but it's a good management tool.

Also, I'm not sure it's meant to absorb large amounts of urine when a dog is fully relieving himself. But it did work great for marking. Since the diapers didn't' quite fit your dog, I'd give the belly band a shot. Best of luck!

I'll try the belly band. I hope it works.