The only way I can even approach even development using Diafine in mine is to load film in every other slot and slosh the heck out of it when agitating. When I do it enough to get even development, though, it sloshes enough chemistry out of the tank that I have to keep adding more in after every agitation cycle.
I'm going to try a run soon with Pyrocat HD and a 5- or 10-minute presoak and not quite so much agitation. We'll see.
I also use it to wash film, but I use it to wash 4x5 POP prints as well.
I also have made a variation of the PVC pipe hair dryer film dryer that uses a plastic bread loaf container (rubbermaid sort of thing from Wal-Mart) into which I put the Yankee tank to dry 4x5 film and prints. works pretty well.
-KwM-