It depends on a few factors. The server load, which affects how fast TK runs. Your connection speed and your local server load. There were a few times where it was lagging and that definitely added time. So, if you were running on a good broadband connection and access TK on a day where the server doesn't have a heavy load, you could probably do it in three hours. Though, it might help to be using two browsers.
The other part is that only 50% of my responses to those threads were 'spam', 'bump', !, ?, or some sort of keyboard mashing. The other 50% of those responses were actual responses. So, if you eliminate the use of real responses, and only use spam responses, that could eliminate a lot of time spent responding.