The closer the better Lee.
If you had absolutely perfect alignment with your mount and scope and camera and all the bits and pieces orthagonal you could theoretically guide on any star in the sky.
However perfection is not always the case (except with the G11 of course
) The more poorly polar aligned you are and the further from your image you are (mainly in declination but RA comes into it too) the sooner you will get rotational issues in the outer limits of your image. The field of view comes into it as well. If you are imaging with a large fov with a long focal length then rotation will happen more quickly as well.