When I made my feeder, I placed the elbow up against the outside of the bucket and drew a circle around the opening. I did this before cutting off the rim of the elbow. Then when I cut the rim off and slipped it into the hole, it was just the right height off the bottom. I've had no problem with feed filling up under the elbow.
I did this with my 5 gallon and 2 gallon buckets.
I did this with my 5 gallon and 2 gallon buckets.