Calling Clock: Part Deux

[CletusVanDamme]

1/2 NL, my first time at the table with about half the players. Other player in hand has roughly $450, I have $500. He seems decent compared to others at the table, but vastly overvalues hands.

After never getting a break against the guy, I see a free flop from BB with J9o. He is button. Flop is QT3, 2 spades. Checked to him, he bets $15, SB calls, I call. (I love having the straight draw on a flush draw board. In my simple little mind, I think this helps disguise my draw.) Turn is a blank, check to button, who bets $30. We both call. Turn is perfect, offsuit 8. Against my nature, I decide to try the river checkraise. Sure enough, he fires $50. I decide on a slight overbet, and push.

As he is struggling with his decision, he thinks for MAYBE 15 seconds, and it looks like he's going to fold. So, I called "clock" on him. He takes another 10 seconds and calls, then walks slowly out the door.

So, calling clock in this situation: rotten move or fair?