The direct way dishes are designed to have alot more gain but should be more difficult to position correctly (to aim it) from its long focus length. If your having trouble getting a bird in with the 39" you might have better luck with the directway dish.
Not only does it have a long focus length its pretty highly parobolic wich gives it the signal rejection of a prime focus dish larger then it actaully is. (I would take a shot at reciving
Cband DVB feeds with one of those if I had one)
a Ku band lnb designed for both linier and circular feeds would eleminate the guess work out of wich type of lnb to get, Sadoun sells a ultra low noise one on the site.