I've tuned to both situations as well.
But like others here, if I have a broad head that weighs the same as the heavier insert, I'd go with the heavier-duty broad head.
Technically, some of the heavier inserts I've used are longer than standard as well. This stiffens the arrow a bit more than a short insert with more weight in the broadhead.
I have versions of the same broad head in 100, 125, 155, 165, and 200 grains. Even have Deep Six ferrules for them if I want super small shaft diameter. I have field points to match all these broadhead weights as well.