I basically do what Seth suggests (hit back) but I know, from watching over his shoulder, that Clint scans the "new threads" page, opens a new tab for every thread he's interested in, and closes it when he's done.
As far as increasing that time... I have no idea. Clint would be the one to ask and he's still MIA for a while. But since he obviously has his own personal way around it, if it could have been extended, he would have done it by now IMO.