Demo Game Help

Gunna be doing some demo games at my lgs tomorrow. We've got the 2 player starter plus the protoss starter to work with and we're using the lists provided in the rules documents.

Should we just use the mat that comes in the 2 player starter? With the game being 1k minerals we're not sure if we should use what has been provided or use the smaller 3x3 mat for skirmish games