Generic 3/6 SB defense question

[damaniac]

Being new to 6-max and fairly new to 3/6 as well, I've been having a little confusion adjusting to both the 1/3 SB and the increased blind-stealing and defense. I am aware that I am pretty much 3-betting or folding vs. a steal raise in the SB, and that most of the time I should fold.

What I am curious about is what hands I should be 3-betting. Take an unknown Button open-raising, a non-super loose BB behind me. I 3-bet Ax/Axs, where x=? Same thing with K's, and pp's. I assume that hands like QJs, while good, are not good 3-betting hands unless the raiser is weak-tight postflop because you are OOP and lack showdown value. As a default I'm 3-betting an unknown with A9o/A8s or so, and KTs/KJo, and maybe 77/66, but I feel like this is too tight. Thoughts?