HU Pot Limit Question

Heads-UP PL Hold Em. Your opponent has 175. You have him covered.


You flop a double gut shot with your J7. The pot is $10. He bets $1, you raise to 10, he calls. You hit the better str8 on the turn, but now there are 2 flush draws on the board. How much do you bet and why?


Thanks,


-Marlow