In reality, neogeo only has 2 layers - the text layer (layer2 in sfact.) and the sprite layer (layer1). That's what we allow enable/disabling of. Looking at both the source of fba and mame, I can't really figure out what designates the sprite data to be different sizes like Kawaks does. If someone could give me a hand with that, it would probably be trivial to add it to the s.factory thing.
best regards,
- dink