Hi guys. I am confused about preflop 3bet sizing.

Here is what i use.

When i am ip..
Vs 2.5bb -> raise to 8bb
Vs 3bb -> raise to 9bb

When i am oop...
Vs 2.5bb -> raise to 10bb
Va 3bb -> raise to ???

Yeah, i am confused which size use against 3bb open raise when i am oop.

I usually 4x vs open raise when i am oop; however, raise to 12bb against 3bb open raise is too big imo.

Any suggestion?