I think the consensus is more than 2-3 drops on the atty will flood it. If you hear a gurgle, or a boiling sound it is flooded. If you are dripping, put 2 drops on the atty (one on each side), put on an empty cart (with no fill) and puff away. Personally I see little difference between dripping and using a full cart other than the carts last longer. I only drip when I am making new flavors. I start with a 6 drop test flavor (3 nic juice, 2 PG, 1 flavor), then if I like it I will make a 1 dram batch.