As a beginner...and really am a beginner, I relied on some tips from guys who had already done a lot of research. For example, a certain Italian gave me the hint that the dial on my 2777-1 was a MoD issue because of the replacement of radium. The internet provides an enormous amount of information....now typically I will take such information with a little salt, but when the information comes from many sources and confirms the same issues, then it seems reasonable to me to take on board some of this internet information. For example, the fact that only 5900 were issued....and of course the final source for me are the Omega adverts which subsequently confirm a lot of the internet information. I think a huge amount of facts can be gleaned from the Omega adverts (which can be found easily on the web, on Ebay etc).