I play with a 10 oz racket, 4.0 level.
Adding 12 grams to 10-12 barely adds anything at all, but takes away from second serves and ease of movement.
I hit with strong SW forehand and strong Ebackhand, not ever flat, so power makes little difference, plowthrough not needed.
First serves, holding well down at the buttcap, plenty of power.
Return of first flat serves, I do need to add some stroke behind my blocking action.