Agree with others, with a 60 series combine the 600 head is the way to go.  625 would work nice or even a 630, either one you will have to pull to move combine on road and a 30 get more done in the field.  If you are always in high yeild beans the 25 might be better.  I would think there would be more 30's out there so you could find one for about the same money as a 25.

Gunner