maybe i'm totally missing what you're asking here...
if you drip and miss the bridge and it hits the "cup" underneath, that WON'T flood your atty. drip wherever you want inside the atty, honestly. if you're flooding it, then you're dripping too much into it, period.
the purpose of the bridge is to wick/move the fluid into the ceramic cup underneath, so whether you drip on the bridge or under it is irrelevant, it all goes to the same place.
but again, if you're flooding, you're adding too much (or too soon). don't freak out about being precise. hold the dropper tip in the atty, add a couple drops. easy as that.
if you're dripping to the atty, DON'T also add to the cart, only do one or the other or you're gonna flood.