Thank yo for sharing your experience. This is such a challenge when I want to keep both birds. May I ask what you mean in your last sentence "when in that position you may find that he isn't such a great rooster after all"? When I initially had the hen separated in the small coop by herself and the rooster was free he seemed fine. Should I be looking for certain signs/behaviours?I had a situation that might sound familiar though it had nothing to do with molting. A cockerel was raised with the flock. Around 6 months of age he started mating with some of the pullets and hens low in the pecking order. Not the hens higher in the pecking order. The dominate hen would knock him off if he tried to mate a pullet or hen when she could see him. As he got older more hens accepted his advances but the dominate hen never did.
When he reached 11 months of age he decided he was ready to take over as flock master. Instead of running away from the dominate hen he stood up to her bullying and fought back. He won. For two days he kept her away from the rest of the flock. If she got close he'd run at her and try to peck her on the head. It was pretty vicious but no blood was drawn so I left them alone, though I did watch. After two days she let him know that she accepted his dominance and they became best buddies.
Some hens will squat for about anything in spurs, but many mature hens want a male to demonstrate that he will be a good father before they let him mate. Cockerels have to mature to a certain point before they can meet those standards. Some hens have higher standards than others.
In my opinion my cockerel was weaker than he should have been. He should have had a stronger personality and been able to win over all the hens based on his magnificence and self-confidence. But that hen was also strong. She was not ready to give up her flock master status. Some hens can be that way. That's not the way it's supposed to work. A hen can be the dominant hen but the rooster needs to be the flock master so he can perform his duties. Dominant hen and flock master are different roles when you have a mixed sex flock.
Each time is different. I had one cockerel be accepted by all the hens at 5 months. That's only happened once, pretty rare. Most if my cockerels are able to take over the flock master position at around 7 months and usually quite peacefully. Then that one time it took 11 months and was violent. The personalities of the cockerels has something to do with that but I also think the personalities of the hens has a lot to do with how peaceful that process is.
You want to keep both of them. At some point he has to take over as flock master. That will happen. That can be violent so there is a risk of injury. I chose to let mine work it out on their own since I did not see any injury. Yours drew blood, you need to separate them. When she heals you can try again and see how it goes. Or you can keep them separated for a while. I would not worry about her completing the molt but more giving him time to mature some more and gain self-confidence so she might be more willing to accept him instead of fighting. To build his self-confidence and just to see how he reacts when he is the unchallenged flock master I'd leave her locked up. When in that position you may find that he isn't such a great rooster after all.