I virtually always pre-click the fold pre-flop if I know I'm not playing a hand, it makes no difference at all whether you do this or not because you're folding anyway. Post-flop, I never use the pre-clicks at all.
I think timing tells
are pretty unreliable online, because somebody that looks like he's tanking could just be in big hands on multiple tables or have a slow connection.
That said, you could certainly pull off something like pre-clicking the check button post-flop in position if you flopped the stone cold nuts, and you think you won't get any action because of the board texture. Some may interpret that as you having given up on the hand and they might try to bluff on later streets.