Smaller broadheads for smaller bows.
Larger broadheads for larger bows.
It's as simple as that.
Just match your broadhead to your equipment, that's the recipe for success.
Now, about the lethality of strong three-blade broadheads, this was just one of five or so of these I found between where my strong three-blade broadhead struck and where the bull piled up a few seconds later. . .
The weight of my bow or my broadheads doesn't matter---only the results. If you want great results, match your equipment well. After that, the fun begins!