Bonding

I have a female rabbit who was spayed 11 days ago (she's ten months old) so I've started to look into getting her a husbun (preferably from a rescue, so that he'd already be neutered when they first meet).
My bunny free roams in my room which is bunny proofed (no cables, slip free mats and so on… Although it is a functional bedroom, so it has a desk, shelves, a bed, so a lot of places for her to jump up and hide away. Although it's not an easy place to supervise due to the many options for hiding).
Also my room is quite small, it does have a cage with her litter box and stuff but it's always open (she's never locked in her cage). I couldn't comfortably fit another cage, although it's doable. and I'm also unsure about the whole bonding process.
Do I have them meet in the bathroom in the bathtub for about fifteen minutes and then have them both in cages back in my room which are close to each other but they can't get to each other? How do I let them get their excercise? Do I let them free roam at seperate times? How would the new bun get used to the room and, well, my closeness?
Also, after I'm sure that they've bonded, I'm thinking of getting rid of both cages and investing in a two tiered one. And is it possible that I think that they'll be fine, and they randomly hurt each other when I'm not looking?

Any tips would be greatly appreciated.

Bunny pic for tax.