Would be nice to be able to specify whether the air blocks in the schematics replace whatever blocks exist in the world. So for example, schematics of buildings pasted into the Lost Worlds mod work fine, but the solid blocks in the schematics replace existing blocks, but the air blocks don't, so in places where there are many Lost Worlds buildings, the schematics merge with the city instead of replacing the city - makes for a lot of cleanup work.