Hi,
We’re doing something similar (with course pages too!) and needed to add the metadata info (i.e. -SF=[L,S,D,J,N,M,C]) into the padre_opts.cfg file for the site. If they’re set there I think they override the collection.cfg settings.
Let me know how you get on - I think I might have some questions about faceted search that I’ll need to ask soon!
Chris