Migrating Cortex Application from Development Board to microcontroller chip
A very quick scan of the datasheet suggests that the VC part is a strict subset of the ZG part. The VC part has fewer pins so you can't use ports F or G, and it has less flash memory.

If my interpretation is correct, and you should definitely spend some time to verify, then any code that runs on the VC should also run on the ZG. I suggest that you try writing all of your code with the VC version as the target. If I'm right then this code will run directly on the ZG part. At worst you might need to tell the tools to assume a different target processor and recompile.