Am I correct that my assistants are over doing it on the liquid by failing to hold the bottle exactly vertical when dispensing? I seem to see inconsistent amounts of liquid in the well after they mix the brush in. They think I am just being picky, but we seem to run out of liquid consistently, more often than not with several brushes left over.If my suspicions are correct, ever think about a longer spout on the bottle to lessen the criticality of a vertical drop.  It is pretty hard to see whether the bottle is vertical from all three planes when it is down on the work surface.  I can often see from my viewing angle that they are lined up good, left to right, but they almost always have the bottle tipped away from them.It’s just one of those small annoyances that would be good to eliminate if it would be possible without much complication.Love your stuff!

As to the drops issue, I've previously calculated that there are 125 drops of liquid for the 100 brushes we provide.  Since the B&B activator brush will activate 1, 2 or 3 drops at one time, there are actually three scenarios.  Either:

1. You consistently dispense one drop per brush, in which case, you'll have liquid left over, or
2. You consistently dispense two drops per brush, in which case, you'll have brushes left over, or
3. You consistently dispense three drops per brush, in which case you'll have even more brushes left over.

In reality, we dentists don't do anything consistently.  We mix it up, depending on the size and quantity of teeth we're restoring.  Thus, you will never end up with both components gone at the same time.  That's why we sell refills.
 
BTW, although not critical for B&B, it's always best if liquid drops are dispensed from a perfectly vertical bottle.  I don't think I'd break out the torpedo level, but the more perpendicular the bottle is to the table, the more uniform the drop size.