That's always a tough one. And it invariably depends on how your rig is built. Perhaps you could give us some detail on the rig design: is it a skeleton deforming a single mesh, are there objects attached to it? Two warnings:

1) watch out for double scaling (If you've got a cylinder and a smoothbound skeleton in a group and you scale the group, the mesh is scaled once AND the skeleton is scaled, which scales the mesh a second time.

2) any seperate objects may need a bit of extra scaling and positioning before they work correctly