When using brass/zinc to manipulate someone's emotions, does it take a full beat to do or is it in addition to your normal action for a beat? The reason I am asking is because the bonus to your charm/influence rolls against the subject require that you continue to concentrate on them and keep burning the metal. If the beat length is, say, an hour or so that could be quite hard to keep the metal burning the entire time so you can get the bonus on your next beat (and thus take advantage of the bonus).
You aren't asking the important question actually. It's not a matter of whether it happens in addition to something else, it's whether it precludes other action - which it does. Concentration prevents you from doing anything else in the same Beat, and in keeping with the one action per Beat rule this means you can't also take another action (that requires a roll) in any Beat when you concentrate.
That still doesn't answer the root of my question though.
The core of the question has to do with the burn rate of zinc/brass and long-ish beat lengths in social conflicts. With longer beat lengths (say an hour or two), zinc/brass become difficult to use since you can't take advantage of the bonus until the next
beat (If I'm understanding this correctly). The reason this is a problem is that you have to burn multiple vials every beat and
stay in range of the target to gain that bonus.
Actually, the core of my issue is the use of both a static duration (burn rates) and a highly variable "turn" duration (Beats). It just seems odd that a highly abstracted system uses very hard and specific numbers for burn rates (rather than something like "a number of beats").