My best advice would probably be: a robo's gonna do what a robo's gonna do
They're such funny little fellas but you never really know what you're going to get. Some are pretty approachable and you can handle them but as they are lightning quick, I'd recommend to do that over a tub or something in case they jump! Some are really skittish and I think so,long as they're OK with your hand in to feed them then that can be enough. I like to think of robos furry goldfish - great fun to watch but not always a pet to, well, pet!
My last robo Hector was an adoption and be didn't like a larger space. He started out happily in a mini duna, I then tried him in a duna multy which he didn't like & then he went back down to his mini duna and was fine again. So I personally think a smaller cage is find, especially when they're getting settled in as I found it made taming easier.
Hector's wheels were either a 6.5" silent spinner (I've had both the kaytee version and the p@h version. The main difference is the p@h comes with a plastic stand which I didn't like and swapped for a kaytee metal stand) or the blue wheel which came in the mini Duna.
As for toys, he liked his cheese cube thing, loo rolls and hideouts so really just anything they can pop in and out of. And he really liked his sand bath. He seems to prefer a little dish that he could run in & out of.
Robos are a lot of fun and I really miss having one. I'm sure you'll get on great.