I was going to also recommend a combination of both approaches. My cracked insert will need to have some surface work done (raised crack edges) & refilled. But that's not going to add strength to keep it from cracking again. Glassing from the back will be required for that (as long as you don't make it too thick to seat properly on the hood).

Since I'm a total goober when it comes to bodywork, I'll get it LineX'd after.