Best Cage for 2 Robo Hamsters??

Robos run a high risk of escape in any cage. Since everything you have mentioned is in fact true, I recommend a middle solution. What I did for my tiny friends was to buy a wire cage, then cover most of the wire in clear packing tape, covering both the inside and the outside. Then I simply cut small airholes, not large enough to escape from, in sections of the tape. It allowed airflow, visibility, and security. It also made their cage look like a hamster version of Hannibal Lecture's cell, but that was cool. Make sure to check the tape every few days, and replace often.