I often find myself adjusting the C'bore depth of a hole to ensure we can use a standard length fastener. This means I have to measure the thickness of the part we're counterboring, and then set the counterbore depth accordingly.
Is there a way to just call out a counterbore depth offset from the bottom of the part so the length of the clearance hole (bottom of the counterbore to the bottom of the part) always remains a constant length regardless of the changing part thickness?
sorry there isn't.
you should create yourself a library feature for common things like this where the norm is to use the opposite side\face to control the offset.
holewiz works the way a machinist does from the face into the part.