Settable still means you need a reasonable default 
One could probably just make a program that loads a vanilla-generated world, walks all the chunks and counts all the spawners that spawn zombies, skeletons and regular spiders. That way we'd have a good-enough approximate of the ratio.
I'm still hoping that R-T-B will chime in here and do the schematics stuff.
One could probably just make a program that loads a vanilla-generated world, walks all the chunks and counts all the spawners that spawn zombies, skeletons and regular spiders. That way we'd have a good-enough approximate of the ratio.
I'm still hoping that R-T-B will chime in here and do the schematics stuff.