How do I search for empty folders?

I'm trying to search for empty folders in my music directory, and I thought I was doing it right, but it's not working. Here are the settings I'm using for the Find dialog:

Basically, I want to find all folders (and subfolders) that are empty. If I don't put that second "AND" condition, then all the folders are returned in the results (obviously). However, if I use any kind of restriction for size, no folders are returned at all. How come? Is there another way to restrict the results based on the size of the folder?

Also, in a related issue, I use the Find-as-you-type filter in the toolbar to filter my directories and files. Here are the settings I use:

Now, I'm using Flat View (Mixed) so I get a list of all the files and folders. Then I type my word in the filter, and the list gets filtered properly for the filenames, but none of the folders get filtered. So, all the folders that don't match my filter still show even though I have the "files and folders" selected in the settings, and furthermore, none of those folders or subfolders contain files that match the word I typed.
The directories are organized:
------music files
So, technically, there are no files until you reach the ALbum folders, but the filter should still be applied to the directory names when I have flat view on.

I must not be understanding something, any help is appreciated.

Sorry, I screwed up with my img tags (how come we can't edit posts here?). Anyway, here they are:

Try this post and the others in the same thread:

[Empty Folders)

Although enough people seem to have wanted to do this over the years that it might be worth asking GPSoftware to add it as an explicit feature of the find/filter system.

Thanks nudel, I didn't realize it was a problem like that.

But, on the other hand, it seems that I can't search for directories of any size, not just empty directories. As soon as I add that AND argument with SIZE, and choose any criteria for it, I get no results. So, is part of the problem that you can't search for folders only of any any size? Does the size argument only work for files?

Correct. Opus won't calculate folder sizes for Find operations.