I'm rather new to blender and am attempting to bake textures (using cycles) I made and applied onto a model in order to export it to Unity. However, many of these textures require the uv map to be significantly larger than the 500x500 square blender gives me. The black box is approximately the size of the UV square:

I know I can create another UV Map, but just like resizing, this ruins how I want the textures to look. Also, it may be related, but blender is kicking me these errors:
I'm rather new and its the first thing I've worked on so heavily texture focused. What should I do to fix this? Do I need to remap and make every material so it fits in the square?
