krlsmnk

Doesn't the Schematica mod do exactly this? Not sure if it uses default structure blocks or its own structure contaiiner, but should work for what you're trying to do. Also lets you "nudge" structures by a few blocks making it WAY easier than default structure blocks. That mod is the main reason I'm anticipating the Forge 1.13 release. Game just isn't the same without it if you're trying to build big.