You said "it takes about 30 seconds to fill in the windows and react to a bid".
Actually what I and many others do when manually sniping is to have one or more bid widos ready filled out and the password entered, and then I keep refreshing the "bid history" page. That way I could probably react, with a bit of luck, to a 10 second snipe. I'd probably fail a five second snipe. A 30-second snipe would be easy! AS is easier still.