Catalogs and Preferences

I have been watching the tutorials on how to set up preferences between Media pro and C1. All of my previous photos have been worked on using ACR and Photo Shop CS5. The preferences are different depending on which program you use.

My ? is, is it better to have 2 catalogs, one for previous photos that were rendered using ACR/PS and a new one for photos from now on using C1? Or can you have them together with settings for C1? Will it make the previous photos not look good?

Thanks Sue