O.L. I've been playing with footings and the internal metal footings in the point of woodies for a while also. As you no doubt know, the 100 grains or so of metal rod in the front does a lot more to increase the foc than a hardwood footing. The hardwood footing replaces wood that was already there so it's only the difference in the weight of the woods, not the weight of the actual hardwood footing, that is added toward the front of the arrow. That may be as little as 20 to 50 grains depending on the woods used, and its spread out over 8-12 inches.
The internal metal rod has a much greater impact due to its heavier weight and placement at the point/front of the shaft. It also seems to strengthen the area immediately behind the head, since the metal rod normally extends back into the shaft another inch or two. Maybe all it does is move the weak/susceptible point back that distance, but so far the arrows I've tested have held up pretty well. Bounced back at me when I shot them into a solid oak, broke the shaft mid shaft on a glancing shot. Need more testing, of course.