UV Maps

Where a map is not supplied for a slot then a regular square or rectangular single texture should be used.

Don't forget you can resize these maps to any size that observes the power of 2 rule.
Any combination of 2, 4, 8, 16, 32, 64, 128, 256 & 512 can be used, with the biggest allowable sizes being 256x512 or 512x256.
I advise experimenting with various sizes to give optimum results.