Dont worry about rep homework. Go to ebay find a reputable dealer ( lots of positive feedback). Look at the exact watch your buying year, model, ect. Compare pics and dimensions Try this site http://catalog.antiquorum.com/catalog_asta...t&s_batch=1
Spend hours looking at fine details. All the dealers outside of a few drop ship so really you have no control over the quality of watch your going to get. Andrews watches seem to be the best of the drop shippers on this site. Im kinda [censored], the last 2 watches I bought have had defective sapphires (not from Andrew). I know if this is happening to me its happening to others. I now have a 5 day old watch in pieces due to a sapphire that the edge basically chipped off. Im searching for sapphires online not my Idea of enjoying my watch.