Do you think that a 4 inch louver will be enough ventilation for a swarm bucket? I just cannot decide what to do with the top. A family member made the swarm bucket for me. The swarm bucket can swivel. The bucket can swivel so that you can empty the swarm into a box or hive. The bucket is attached to a steel "u" shape. The steel "u" is made from plain flat steel stock (1/8 inch thick by 3/4 inch wide by 48 inches long). You can use a vice to make the "u" but the bucket should clear the bottom. In order for the bucket to swivel it must clear the bottom. The bottom of the bucket is attached to the steel "u" with a 5/16th bolt flange. The two sides of the bucket are attached to the steel "u" with a 3/8 inch hex bolt. The bucket should have a good shoulder so it is kind of smooth (a good heavy food grade bucket). Use about 6 washers (3 on each side) so no metal edges rub the plastic. The 1/2 inch by 48 inch pipe screws into the flange at the bottom of the bucket. You can extend the pipe with a 1/2 inch coupling. I have an additional 1/2 inch by 48 inch pipe. So my bucket at full extension is the bucket the first 48 inch iron pipe, the 1/2 inch coupling, and another 48 inch iron pipe (if I need it). I am not sure what to do about the cover.