Not too sure why it should be offset but was told by several different peeps that that was the way to do it. Certainly works well. As Richard says, maybe something to do with having the trailer near to the driver's eye line. You can also have the trailer at almost 90 degrees to the vehicle and still carry out precision manouvres. Will try and find out why.
Peter (nick, nick) T
Age and treachery will always overcome youth and skill! Bullshit and brilliance only come with age and experience.