Bet size when you flop the nut boat? Positional considerations...

[Peoples Elbow]

Don't have HH, but recalling a situation that occurred the other night.

$50 PLO 6max table on FT.

UTG pots it, UTG+1 calls, I have something like:

9[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/diamond.gif[/img] 8[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/club.gif[/img]

Everyone ends up calling, 6-handed we see the flop:

J [img]/images/graemlins/spade.gif[/img] J [img]/images/graemlins/club.gif[/img] 9 [img]/images/graemlins/heart.gif[/img]

Checked around to me, with ~$8 in the pot and everyone with ~$50 effective stacks, what's my bet?

I'm assuming I don't want to give a free card here as my hand is still vulnerable, so what's a standard bet given I'm in the CO and it's been checked to me?

Also, I'm curious what you think I should do if I had this situation but I was the SB and first to act postflop, do I check and hope to get in a big check raise?