UVs and Materials?

Hi, I made building floor in blender and I use RGB masking to texture and keep everything as one object.
This time I require more that 6 textures for my object. My question is should I place the extra to another UV channel or to place extra as separate object, what method is more efficient?

Another UV channel would be more efficient if possible. Otherwise you can set another material ID for those parts and use one more material.

To add to Jacky’s information you can take a look at our Documentation on Custom UVs, which will give you information on the performance benefits when using custom uvs.