Sounds like you got the coveted “love at first sight” bunnies! But you also had good judgement to not rush things. 🙂

You can definitely do an overnight now, but you will want to supervise. That means setting up somewhere to “sleep” near them so you will hear if a fight breaks out and you can intervene quickly. I put sleep in quotation marks because I find I never do much sleeping because every little noise will wake me up! So best to do this when you don’t have work the next day.

In terms of determining if they are bonded, the rule of thumb I go off of is they should spend 48 hrs together with no fighting or aggression that needs intervention from you, and lots of positive behaviors (cuddling, grooming, food sharing, litter box sharing). Then every time you move them to a new location (such as the move from neutral to their final home), you will want to supervise them again for at least 24 hrs, but preferably 48. The overnight supervision tends to be the most important because that’s when the buns are more active.

It’s also OK to separate them if you need to step out for a bit or take a nap, as long as they can see each other it won’t set things back.

So the timeline I often use is set them up in the neutral spot you will use for the overnight. If the first overnight goes well, I keep them together in the neutral spot and I start cleaning and rearranging the area they will live in permanently (or getting a semi-neutral transition area ready, if you have one). Then after the second overnight in neutral I move them to their final home. If you have a few issues at first in the final home you may want to supervise them a bit more just to make sure they are good, but if they are good the first 24 hrs they should be fine!

If you don’t have that much time to supervise constantly, you can separate them when you need to go to work, etc. My first bond I never did the “marathon”. Once they were good for multiple  6-8 hour sessions during the day,  I did a few overnights (with day-time separation). After the second (or third?) overnight I moved them to their final home and supervised for the first 24 hrs.