IMHO it depends enormously on the velocity achievable, relative to the threshold for hydrostatic shock. The general agreement is that it occurs above perhaps 2350 fps, give or take, depending on personal experience or who you listen to. If the lighter bullet will put you well above this threshold, and the heavier one won't, then there is definite merit in the lighter bullet (for thin-skinned game, as stipulated).

If neither bullet will exceed this threshold, then go the heavier one every time.

Very few of my serious hunting rifles exceed even 2150......

...so you know where I stand!