Ask five different chicken keepers about roosters, you'll get six different answers, most of which are dead opposite to each other. There are so many variables. If someone tells you their way is the only way, they're talking nonsense. For instance, there was something said about feet not being a good way to move a rooster. In my experience, hands actually set them off worse.

See what I mean? Body language is so subtle that two people that try to do the same thing may be sending completely disparate signals to the bird.
I threw
out the book, after trying and failing to use it. I went by common sense, and if something didn't work, I tried something new with the next bird. I ruined a few roosters along the way, but now every rooster I hatch and raise is respectful and trustworthy around people. Personally, I find that my roosters do still come investigate when I pick up a hen. Their behaviour does not read as aggression to me, it's concern about their hens. I ignore it or perhaps move into him a step (or maybe just lean towards him) to switch his interest away from the fact I have a hen. It's very subtle movement. Not confrontational at all.
In general, I don't class different behaviours from a rooster as aggressive or not because it's the manner in which it is done that matters, in my experience. A dropped shoulder, for instance, can be innocuous from one bird and signify an imminent attack in another. Look at where he's directing his focus, listen to his vocalizations, and make your descision from there. Roosters are the best and finest teachers in raising chickens that one could ever hope for. Alas, they lack the capability to speak English.
https://www.backyardchickens.com/articles/a-viewpoint-on-keeping-roosters.74690/
In case you're not confused enough already, here's the post I wrote up for someone else that wanted some input on their cockerel.