A split set separates parent games from their clones. A clone zip file only contains the unique files that differ from the parent game. Saves a massive amount of storage space.
You must use an emulator designed for 0.78, specifically the MAME 2003-Plus core in RetroArch. mame 078 romset
A complete non-merged set (including CHDs) is roughly 30–50 GB . Understanding Set Types A split set separates parent games from their clones
Highly organized and saves a significant amount of storage space compared to non-merged sets. mame 078 romset