River bet sizing

Does this look ok?

***** Pacific Hand History for Game 184253763 *****
$0.5/$1 Blinds No Limit Hold'em - *** 01 26 12:40:34 2009
Table Hand Grenade (Real Money)
Seat 6 is the button
Total number of players : 6
Seat 1: maipenraii ( $101.1 )
Seat 2: LolUrASlave ( $121.54 )
Seat 5: Behle83 ( $107.85 )
Seat 6: goldin38 ( $78.9 )
Seat 8: Paran0ia ( $115.31 )
Seat 9: Angkev1 ( $69.93 )
Paran0ia posts small blind [$0.5].
Angkev1 posts big blind [$1].
** Dealing down cards **
Dealt to LolUrASlave [ Ks Qc ]
maipenraii folds.
LolUrASlave raises [$3.5].
Behle83 calls [$3.5].
goldin38 folds.
Paran0ia folds.
Angkev1 folds.
** Dealing Flop ** [ Js, 6h, 2s ]
LolUrASlave bets [$6].
Behle83 calls [$6].
** Dealing Turn ** [ 6c ]
LolUrASlave checks.
Behle83 checks.
** Dealing River ** [ Ah ]
LolUrASlave bets [$12].

Yeh about right imo. I think opponents will have quite an inelastic calling range here. You're rarely folding Jx out regardless of your betsize, so i want to bet smaller to get better odds on my bluff. In situations where people tend to have really inelastic calling ranges, you really want to switching up your betsizes quite a lot if you're aiming to play maximally exploitive.