Replacement:
With all due respect to your skills and knowledge, I still have doubts. It all depends on your definition of "stronger." (forgive me Bill Clinton)
I use these glues and resins too. But NOT in an effort to reverse the ravages of time. While they can probably make a cleansed stock head more solid, that value does not necessarily equal "strong" in terms of what a gunstock must do.
In many cases, a stock must flex and compress under the force of recoil. A resin impregnated stock head can't do that very well.
So... "you picks yer stuff an takes yer choice" here. A pretty and reconstituted stock head may serve well for another 100 years. It may also break next month.
It's all in the hands of Mother Nature -- and physics.
I always recommend modest loads in any gun repaired in such a way.
