nazcar_steve: Very interesting about Sky Dump (Skyspot) and blind bombing, and of course your RAAF stats on accuracy and minimal losses compared to B-57 crews are worth noting. That said, I am not making a truly fair comparison considering the USAF role for the Can was more of an interdictor-bomber, and in no way meant as a sleight on the American crews who were bloody brave and professional too.
Yes - the RAAF Canberra only operated in SVN, and not "up north", or supposedly in Cambodia or Laos, where a lot of the B-57 work was done. RAAF missions I would estimate to be about 20% skyspot, and 80% level visual bombing under FAC control, over the years 1967-71.
They were embedded in the 35th TFW at Phan Rang as there were 2 ANG B-57 units there - I think 8 TBS and 13 TBS (or was that TFS?) - but these were replaced by F-100s by 1969. The US crews were great - but operated in hotter places and in a very demanding dive bomb role.