Thanks all.. Nutty it's nice to see your pictures. I am a visual person. Windows were always more interesting than school books.
Luckily, I do not have a pebble in my sandy soil. Great advice about turning to the Left.. turning right was creating a whole different scene (mess) at the end of my rows. I can see why they added a dolly between the gangs ..then have 3pt. for smaller ones.
..and it makes sense; if the fronts do more work, then you would replace them first. I thought there might be some 'science' about Lg/Sml.. but it's just being practical/frugal.
Graham - you're a luck fellow with such a beautiful country. We Yanks get to visit it by simply going to the movies.