I just noticed your post this morning and was surprised no one has replied.
I think your situation is salvageable. The link you provided gives some good suggestions for breaking up a fight (water pistol is a good one or throwing a toy or pillow to redirect attention). It's not a good idea to intervene and break up a fight. Too much of a risk of injury to yourself if cat turns on you. I don't like the idea mentioned in the link of "scruffing"---grabbing by the neck and gently holding cat down. For some cats this doesn't work and only infuriates the cat further and then you're the target rather the other cat.
The fact that Bruce still wants to nurse on Madison could be a factor in her attacks. I would discourage him and remove him from her if you see him doing it. On the other hand I have had some females that encouraged and enjoyed it! but it really depends on the individual cat.
The fact that Madison has not drawn blood or broken skin or really injured Bruce sounds to me that she's really just disciplining him...maybe she really is fed up with his nursing after 3 yrs.
Try on getting your cats' attention focused on you. If they do not come to you when you call then, start by teaching them "to come" by offering treats. After they're coming consistently to you, you don't always
have to offer a treat, but can reward with lots of "good boy" or "good girl" or chin scratches and caresses/tummy rubs whatever the cat really likes, or offer a catnip toy. Whenever it looks like Madison is going to attack, call her to come. If she attacks 'out of the blue' use a water pistol or some other distraction and say a loud "No! bad girl!" Walk toward her by stamping your feet. Most cats don't like that. Any positive
behaviour you see between the cats, e.g. sitting close together, praise them with a "good boy"/"good girl". You want them to be clear on what behaviour you approve of and what you don't.
Hope these tips help out,
and an update would be nice.