There is no hard and fast rule to this, it will depends on your project, style and design.
That being said, I generally use larger layers spaced out farther, it’s always easier to make a layer smaller than larger. I find it’s easier to move a camera if I have larger layers, can space things farther apart and create long smoother moves. You can make those moves with smaller layers, but with everything packed close together I find it more difficult(I like to create the illusion of parallax and to do that with everything right next to each other is more challenging). Check out this tutorial from VideoCopilot to see some nice moves and parallax.
Of course you can only work with what you have and if a client provides you with small layers, that’s what you got to use.
Johnny Cuevas, Editor
Thinkck.com
“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.