The other thread suggests that the really keen manual sniper has a good chance of managing a response to a bid at 6 seconds. That is 4 seconds for the refresh reporting the bid (assuming the sniper sees a refresh every 2-3 seconds), a second to hit the button and a second for Ebay to deal with it. However, I am not sure I believe that and the probability that it would fail is quite high. In any case, I believe the number of people waiting like that is low.
I will stick with my current 11 seconds on Sunday night (not on the hour etc.), which is actually 12-14 seconds. I think the chance that I lose an item because of a successful reaction to my bids is as low as the chance that I win an item because I bid before another sniper.
