Those are not the strongest.
Especially Bromazolam is not that strong (It is a very functional benzo though, because not sedating and quite safe).
If you are looking for really strong Benzos, try those who have notable effects at doses of 0.1mg:
Flualprazolam
Flubromazolam
Clonazolam
There are yellow pills of 1mg Flualprazolam. For normal people, if they just nag a little bit of it they can't avoid falling asleep. It's incredibly potent and sedating.
Flubromazolam has the worst reputation of all Benzos. There are some reports of victims dipping two tiny crumbs and the next thing they remember is 10 days later when they wake up in prison after 2 car crashes and multiple other felonies. Of course they don't remember and never will.