When an enemy is trying to hold attacks - I simply throw a hit with the same direction of his held attack. If he releases the button - he either chambers my attack (and I block it afterwards)
This is not how it works. You can only chamber an attack by drawing back your weapon (starting an attack) not by releasing it...
I my experience chambering held attacks is mainly luck or just getting a feeling of how long your opponent holds his attacks.
If someone is "ever-holding" you can always try to attack the same direction and hope that you will be lucky.
But there is no reason to try chambering >1 sec holds, since if you miss the chamber he will hit you before you hit him, and depending on your weapon and WPF you might not even be able to retract your attack to block his.
In my opinion holding attacks is too powerful. There is hardly no incentive not to do short holds (>1 sec) against decent players who do not spam randomly.