Well, there are two methods to feeding a cart/atty on a bottom feeder BUT, one method works better for carto's.
You also lightly squeeze the bottle. Taking a dry hit at the same time while squeezing the bottle. Once you hear a little bit of gurgling then you stop after a couple of seconds. Followed by a few more dry hits to pull the
juice from the bottom to the rest of the carto.
Anyways, you will be the determining factor in deciding if it gets flooded or not. If you feed it to the point where it's mushy on top then you've flooded it. Personally, I look to see if there's a little color or
juice that's on top to let me know that the filler has been properly filled. Some people actually squonk it every 10-15 hits like you would if you were topping it off (same thing really). All other rules will apply such as waiting until you taste a drop in flavor, etc.