Easy Way to See File Size Distribution?

I'm looking into adding some ssds as a metadata+small file cache for a freenas server. I want to make as much use of the metadata vdev as possible, meaning I want to cache as many small files as I can, without exceeding capacity.

The freenas server is mixed use (personal). So it has everything from photos to games, AI related shenanigans and more. There is no set file size for anything like in a database server.

I could guesstimate the size limit for how small a "small file" is. But chances are I'm going to vastly over or undershoot the actual mark. Is there a program or command I can run to help out?