Wheel for Robo?

[a680]

Hi all(:

I'm about to be a first time Robo owner in a couple of weeks !
I've never owned a Robo or hamster that small so I've no idea what size wheel I should be getting? I'm rehoming my friends as he doesn't have the time for it anymore so I've seen him and he's a tiny little thing.

I've been looking online at a 20cm trixie wheel and another wheel that's the silent spinner 6.5 inch but as I said I've no idea whats suitable and best for a Robo hence why I'm here for info before I take him(:

What wheel size do you use for your robos? Are either of the ones I suggest suitable? Is there such thing as too big ? I have a big wheel I used to use for my Syrian and my dwarf hybrid can use it but he finds it difficult to get it started which I wouldn't want the robo to have that issue (the dwarf has a smaller wheel now) and what brand would you recommend also(: