Hi there!
I got my Robo about a month ago and 493 sq is above the bare minimum 450 which is good. I would suggest sizing up if further down the line your hamster starts to seem bored.
Just so you know, connecting two enclosures together does not equal more floor space. Hamsters need continuous floor space for it to be beneficial, however, if you still would like to connect a separate bin I would suggest you have either have it filled with very deep bedding (7-10 inch) so that bin can be used just for burrowing OR put sand in that bin, Robos LOVE sand.
Hope this helped
