5/10 10-500, TPWK vs. nutbar, what is your line?

[cpk]

This is a live 5/10 10-500 game at Tulalip. You have K[img]/images/graemlins/diamond.gif[/img]8[img]/images/graemlins/diamond.gif[/img] in the BB in a game which is very loose and passive preflop. UTG+1 is a nutjob who doesn't raise a lot preflop but very aggressively bets postflop and will fire three times with garbage. On the other hand he is not a complete idiot and will fold fairly good hands if he perceives he is beaten.

Your stack: $500
UTG+1 stack: $1300
Others: not relevant

The action so far:

Pre-flop. 9 players. UTG folds, UTG+1 calls, 4 callers, SB completes, you check.

Pot: $66. Flop: K[img]/images/graemlins/spade.gif[/img]9[img]/images/graemlins/diamond.gif[/img]5[img]/images/graemlins/club.gif[/img]. 7 players. SB checks, you check, UTG+1 bets $50. Everyone else folds. What is your line?

Extra credit: What if you had $1300 also? Would it make a difference?

I think the line I took was reasonable under the circumstance, but I'm curious to see what others think.