I think the problem in this hand is from taking control of the hand betting with ur amazing draw on the flop OOP. If its checked around to you thats one thing because this is a good enough flop to get urself all in on the flop, with the dead money that will develop. By leading out you are causing a lot of trouble for yourself on the turn and river because you will have to check a blank just like you did. However, if CO had more money after his turn bet I would make this call because ur implied odds would be insane for quartering him. I think that u have to put him on a hand like A2kx or A2Qx at worse which means that u r looking for a A26 to quarter and a 3 to split. However, if you do hit ur A2 or 6 and he still have more than a pot bet left I would make this call because he is going to put his whole stack in with a decent high and the nut low and you will get a huge chunk of his money.
This draw is sweet, but I dont like building this pot from OOP on the flop and having a costly turn to see. Just check/call or check/raise pot this flop (although i would probably just check/call). Then when u call this turn bet he still have more in front of him so that implied odds are there and the pot is small. Also, its much easier to fold if usr still not getting the implied odds ur thinking because u have less invested. Or, he might get scared by ur call and just check the turn and u will get a free river. I just think that ur chances of winning the hand go up significantly by checking this flop.