Honestly your sessions sound pretty typical. I agree that the lunging at the cage isn’t good, but the sessions don’t sound all that bad.
This bit: “spent the first 8 minutes exploring the area and briefly crossing paths. When they came close to each other I pet them both and they were lying down which lasted for about 3-4 minutes…. The session ended with them ignoring each other and her grooming herself for a few minutes. ” sounds pretty good to me, and fairly typical of an early date.
So whenever you decide to resume sessions, I would keep using that space, and using the approach you used already, with petting them both to prevent escalation of things.
I think it’s important to remember that rabbits are aggressive out of fear. Your boy at this point is behaving in a way that suggests he sees your girl as a threat, but not a terrible one. It’s good that she isn’t really retaliating. With time, he will learn that she is not a threat and then the bond can be formed. I think the larger space is good for you, because it gives her space to retreat to, and allows them to interact more on their own terms (vs. being forced together in the tub).
Focus on building trust between them, by petting them both anytime you think things might escalate beyond light nipping.
You are right in that patience is important! Even if it seems like nothing is happening, and they are ignoring each other, they are actually sizing each other up.
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.