Thanks for the response. The 24-inch bucket is all I have and all I need, except for the interference issue with the two teeth on the thumb.
I will consider buying an 18-inch bucket if the teeth on it are differently spaced.
I have no use for a "landscape" bucket with no teeth, although that would work with the thumb.
I have a thumb, but it is not OEM, and does fit between my 24" bucket teeth.
I also have a 16" 3-tooth bucket, and my thumb works with that also.
The 16" bucket teeth are all mounted straight - no outward flare.
I have a piece of bucket cutting edge welded to the inside of the outer two teeth.
This gives me a smooth bucket edge ( your thumb would grasp it securely).
I can drive the two outer teeth pins out, swap with two other teeth, and be back to a three teeth bucket.
This will only work with the 16" bucket as the outer teeth are flared outward on other buckets.
ie: I have a smooth edge bucket, and a tooth edge bucket for one price,
Extra buckets are EXPENSIVE!
I do have the Kubota BH bucket quick connect coupler.