??? on printing size

[eeyoremommy]

I know I was reading earlier about the size that people print out their disigns for magnets. I was curious about printing the Mickey heads. What size do most of you print them? Our printer does 8 x 10, 5 x 7, 4 x 6, and 3 x 5 (like most printers). I'm guessing 8x10 or 5x7???? Suggestions???? TIA.
Sherry