flush draw continuation bet

1/2 no limit cash game again guys

me: 150

tight guy: 250

sold player: 350

new player: 225

i look down at 8s 7s and decide to raise an unraise pot and make it 15 total to play. the tight player is in the big bling and he calls, the soild palyer whom is two seats away from the big blind calls and so does the new palyer whom is two seats away from the soild player.

flop: Qs Js 6d check, check, check to me i bet 30 bucks into a pot of 60. Is this too little? I then get a call of 30 by the tight player. What does this mean? The next card is a blank and he checks. Do i fire a bet and if so how much or do i check and see another free card? What do you guys put him on

(I'm not too good at putting people on certain hands but I'm gonna give this a shot. Constructive criticism would be greatly appreciated.)

I'm assuming that by you only mentioning BB everyone else folded to your bet? he called a 6.5x bb bet preflop and he's a tight player. Automatically I would assume he's holding high cards or a pp. Maybe 77+ KJs+ AQo+ A10s+.
You have postion after the flop, bet half the pot and he calls. At this point I would narrow down his cards to either a draw or tp or maybe even both. KJs+ AJs+ maybe AQo+ although I doubt it.
The fact that he didn't push this makes me believe he's drawing out. If he wasn't looking for a draw to the nuts I would think that he would have pushed back so that YOU didn't draw out on him.
I would fire again on the turn at least 2/3 pot. If he calls this then I don't know, this is where my game starts to go bad.

I would probably bet 3/4 pot. I want to make it look like I'm forcing out a flush draw with a big hand.

You can be sure he's got queens or better. Hopefully you hit your spade draw, cuz if not, you're going to have to drop this hand.