[cypher]

I wouldn't recommend an Alaska due to the height, most Russians will bar climb if they have the chance & there is a real risk of injury when they fall.
If you want a bigger cage then something like the hamster heaven (best used without the tubes & penthouse) is a more suitable option.
What size wheels do you have? They look quite small but it is a bit hard to tell.
Even if your ham appears to like the ball it's still not safe for them.