X/r flop. As played x/r turn. And no you should not 3B preflop HU out of the BB unless CO/BU will open a wide range and become passive, or have an unbalanced checking range OTF.

Are you not worried about balance here?

What would constitute balance? Likely bets lean heavily towards aj-ak, a small number of set combos and a very small number of straight draws / board pairs / air. Even with 4 live outs they’d be close to having odds to call (with implied odds) assuming you had zero bluffs, and then they’d call river with a ratio of hands to make river bluffs break even if playing optimally.

The number of straight draw bluffs you need to be balanced is very small. If you can have an oead based on preflop action then that would probably be your primary bluff, and if not it would likely be a small fraction of other hands that have less equity like gutshots or underpairs that are borderline folds.

The worse your equity when called the more infrequent the bluffs should be, and when when laying him 8:1 it should be pretty infrequent in the first place.