I've never been able to reform a rooster of any aggressive behavior. I've had to get rid of several over the years. Some received pretty nice homes, others became someone else's dinner. The worst ones only went after me for a while, and yes, I tried very hard to assert myself. I never turned my back. Well, things changed when one of the boys started going after my 5 year old brother and drew blood in his leg. After that, my family was starting to fear leaving the safety of the house. So I had to make the sacrifice, even though I had a thing for this cockerel.
I do not agree with any methods of physical violence. Roosters are chickens. Animals. This is what they do. But we are capable of hurting them alot more easily than they are of some of us. If a rooster cannot be rehabbed the normal ways, they cannot at all.
Options are very limited. In my flock's younger age, it killed me to get rid of any birds. They were pets with names. But things start to look different after a while...If you want a rooster that won't attack, it'll be trial and error. Sometimes you have to get rid of the problem and wait for a new boy to come along. That's what I did. I had terrible roos in my flock until I found Rocky (My Rocky is nice, lol), who didn't exactly have a loving home. He does today. Now I have the best rooster I ever had guarding my layers.
As for my Silkies...well, sometimes that fiestiness comes in handy. I like my roos for different reasons. I don't breed mine so I'm not worried about bad behavior passing on in bloodlines. Crix is locked away most of the time, but I keep a warning close by.
Good luck.