Alex, though this may sound smart-alexy, it’s actually a straight answer: Just go to a heavier head. It’s better than internal or external shaft weights because the further forward the weight the better for FOC, and also because heavier heads, like the Tuffhead 300 I use, use thicker steel which not only makes for an overall stronger head but also, with single-bevel, the extra blade thickness allows for a wider bevel shelf which in turn enhances torque.
Dave may be right Alex. I have some micro shafts with external Al footings, but they’re only worth about 25 grains. If you have an adaptor in your arrow that may be a cheaper change than the broadhead.