[LunaTheHamster1]

I would say it's fine if you placed another hamster in henry's free roaming place. As long as he can't interact directly with the other hamster. e.g.. bar cage on the floor and henry can go up to it.

Not sure how you have Henry's cage but is it possible to build a shelf above it and place another hamster cage on that?

I'm like you I prefer the bar cages, but I have been experimenting recently so I can get more substrate and tunnels in - I have used both cardboard on the outside of the cage, tied with jute and also tried waterhyacinth mats tied on the inside of a cage.. So far I think the waterhyacinth mats look nicer, but both do a pretty much good job at keeping the substrate in the cage. The problem with the cardboard on the outside is substrate gets stuck between the cardboard and the metal bars. Which is fine, until I lift the cage off if I am doing a big clean. Like I said it's an experiment, but it works quite well.

I hope you can work it out that you can find space for another cage and hamster - so excited for you if you do.