Needle size is user preference, if you are a loose knitter a smaller needle will help the pattern to be seen better. Most needles between US3 and US8 will work well.

There is no gauge for this pattern and finished size s/b between 8x8 and 9x9 depending on your tension

This cloth will use up less than a ball of cotton yarn. I recommend a solid color and suggest you avoid very dark or very bright colors (ie: black or neon orange etc)