HU in $24, 5k gtd. on FT: Bluff river?

[Chipchucker5]

Villain was pretty straightforward and kind of weak-tight (i.e. folding to most flop cbets). You like bluffing the river? If so, how much do you bet?

Hand History converter Courtesy of PokerZion.com

Full Tilt Poker Game #3681842339: $5,000 Guarantee (27564623), Table 17 - 5000/10000 - Pot Limit Hold'em - 21:39:07 ET - 2007/09/26
Seat 3: COOKIEHUMPER (181,000)
Seat 5: barry manilow (494,000)
barry manilow posts the small blind of 5,000
COOKIEHUMPER posts the big blind of 10,000
The button is in seat #5

Preflop: Hero is BB with 7[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/diamond.gif[/img].
<font color="#CC3333">Hero raises to t25,500</font>, Button calls t15,000.

Flop: K[img]/images/graemlins/club.gif[/img], Q[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/spade.gif[/img] (Pot is t51,000)<font color="#0000FF">(2 players)</font>
Button checks, <font color="#CC3333">Hero bets t30,000</font>, Button calls 30,000.

Turn: 4[img]/images/graemlins/spade.gif[/img] (Pot is 101,000)<font color="#0000FF">(2 players)</font>
Button checks, Hero checks.

River: A[img]/images/graemlins/diamond.gif[/img] (Pot is 101,000)<font color="#0000FF">(2 players)</font>
Button checks, <font color="red">Hero?</font>