Ok, decided to give it a go, since it's been almost a month since neuters. This time I opted for the travel cage on top of a running dryer (with lots of clanky clothes). I started with two small cages next to one another, & Bosco was noticeably scared but not huffy, so I gave it a go. Things seemed promising, with both rats running around the cage to figure out what was going on. At the beginning stages, Bosco even tried to squeeze under Bug, & even turned himself over halfway. I kept them there for about 15-20 minutes with confidence building, & had a little jar of coins to shake if things looked like they might get heated. Things were going really well, & then both rats assumed full stance & had a rolling fight, which was quickly broken up. I then tried to keep Bosco in that slightly scared state by picking up the cage & walking with it, & also occasionally shaking the coin jar, but after that both rats pretty much hung to their own side of the cage. I gave it another 10 minutes or so, & then put them back in their own cages.
I'm assuming that all still has some promise, & my gut would be to keep doing that same dryer/travel cage intro daily until they get used to one another. Does that sound right, or am I doing anything wrong? Any other advice?