No reads on the villian - he has just joined the table.

I considered checking the turn but felt I should charge the draws and weaker queens, possibly getting a third value bet in on the river also. Comments on the play in general appreciated.

$0.50/$1 No Limit Holdem
5 Players
Hand Conversion Powered by weaktight.com

Stacks:
UTG ($62.84)
CO ($162.27)
Hero (BTN) ($101.10)
SB ($101.34)
BB ($23.15)

Pre-Flop: ($1.50, 5 players) Hero is BTN A Q
2 folds, Hero raises to $3, SB calls $2.50, 1 fold

Flop: 10 5 Q ($7, 2 players)
SB checks, Hero bets $4, SB calls $4

Turn: 4 ($15, 2 players)
SB checks, Hero bets $9, SB raises to $28, Hero folds

Final Pot: $52

Uncomfortable spot. As played, I think I need to call and reevaluate river. Bet sizing is a bit small imo and may have induced him to try to take it away from us. After all, what is he repping with a c/r on the 4? I would suspect a flopped hand or air. As far as bet sizing, I would likely bet 5-6 into the $7 pot on the flop and 13 or 14 into the pot on the turn.

i def like a fold here...his bet sizing suggests 2pr or better. He doesn't appear to have a draw so id think if you call your looking at another bet on river.

How much player are capable of taking a c/c c/r bluff line in that spots at NL 100?

If you think a player is bluffing then you can play the hand differently. This looks like a case where we will have to play a huge pot in a guessing game situation if we are thinking he is bluffing. Notice the hand is on the turn so further betting weather for value or bluffing will occur on the river most of the time.

Dislike betsizing on both flop an turn. 6 on flop and (as played) at least 12 on turn seem way better. Ohh, and I might raise smaller preflop with a Shorty in the blinds (though against some shortys, I'm staying higher to induce their shoves).

Based on this I am more inclined to call, as your hand might be assumed as weak based on this. But with the complete absence of knowledge and zero history, it is always hard to assume he might turn his draws into bluffs. On the other hand I don't see many value hands in his c/c c/r range on this type of board. Sets and QT should often be check raised on the flop.
Thus I call and I am inclined to call a safe river, though betsizing is of interest in this question.

My standard raise on the button is generally 2.5bb or 3bb as I steal often so generally a smaller raise size is better as the average strength of my range is weak.

Likewise, I often c-bet the flop and generally make the bet as small as possible to get folds when I miss. Betting big when I hit and small when I miss seems exploitable. Making big c-bet all the time also does not seem terribly optimal.

I think the turn bet could have been a bit bigger though.

Exploitability on Small Stakes (especially NL100) is one of the minor issues to care about. As long as it is not exploited (which does not happen often enough to assume every unknown does it) it is not exploitable. How ever by giving villain good odds to draw on a very drawy board is indeed exploitable and will be exploited (conscious or not).

You should not bet big all the time, but should trim your cbet to board texture and type of villain.
Also, on your very first cbet (maybe the second as well) against someone, you can use his lack of information to tailor your betsize around what you want to acomplish, rather than what would be unexploitable.

i would c/c turn, but the way its played it looks like villian has u crushed tuff laydown
10-Q, 5-5,4,4. all probable hands

default should be to bet more on turn/ fold

That is an interesting post. I am experimenting quite a bit with different c-bet sizes. It is something I find hard, thank for the input!