welcome back! i think it's great you want to get Ruffles a friend!
in my experience (which is limited to bonding one pair), a good bunny is not going to become a bad bunny. my mini rex stills loves attention from the family. she is still perfectly littertrained (post-bonding that is). she still likes to dig on the couch and chew on the walls. i have noticed the destructive behavior has decreased in frequency and severity... but again, i don't know if that's related to her new husbun... or if it's a natural progression of her getting older (she's now approx. 3 months shy of 2 years, she's been spayed for just over a year).
xpens are awesome! absolutely. they can easily be moved away from the area so everything can be thoroughly vacuumed/wiped down. my personal issue with condos and traditional cages is that i feel you will never get it truly clean. if your bun is used to levels, what you could do is construct out of wood a side ways "E" ledge so they have a place to jump up onto, or some boxes work just as well if they want a bit of height.
i know this will not work for everyone but i purchased two xpens and put them side by side and switched the buns in between them every night. you want to eliminate any territorial behavior towards the cages. i would leave your bun where he is for now until you know for sure what your timeframe on bonding will be. it was quite easy because when mine were ready to be together 24/7 i was able to combine the two pens so they had a very large permanent home. i also had a whole room just for them tho... so like i said, this might not be possible in your case.
bondng bunnies can be complicated. love at first site is rare. i would expect for it to take at least 2 solid weeks of everyday bonding sessions. mine took 3 weeks of one-hour-a-day bonding.
what you want to do is rescue a bunny that is already altered from a shelter/rescue. this is great b/c you can start bonding from day 2 and you don't need to worry about altering yourself, waiting for healing, etc.
if at all possible, take Ruffles with you and let him meet several eligible bachelorettes and make his own choice. this might help you bond them faster and easier.
a low-key, non-aggressive bunny to you might not be so easy-going when a new bun intrudes on his space. it is important that you have some kind of neutral area (bathroom, empty walk-in closet, laundry room, your bedroom) where you can introduce and do the sessions. you're fortunate b/c in some cases it is easier to bring a female home to a male... but as you know with bunnies, there is never any sure thing.
what i'd suggest you do is read thru some of the bonding threads here. the ones where the buns have successfully bonded and the experience is documented start to finish are marked with a "bonded" after the subject...
also, this is my favorite bonding article, read it, print it, re-read it... it is great! http://www.rabbitnetwork.org/articl...bond.shtml