You do not need a wide board (especially Never summer wide) with a size 12.
I wouldn't go above a 26.0 cm waist to be honest. You can have some decent overhang before you start getting toe drag. If you get a board in the 162 range, you will already be in the high 25.x cm waist range with a normal width board.
With the hybrid camber shapes out there, you will already have better powder performance regardless of what you get (vs. a camber board.)
It sounds like you want a setback, directional freeride deck. If you plan on doing more spins and switch riding though, you want to go for a twin shape.