[Betty]

You can click on the gradient tool and then up in the corner on the settings for the gradient. Sorry - I don't have photoshop on this laptap to be more specific. But you can change the colors of the gradient and add in more bands. Clicking and dragging them changes how narrow or wide the band is. To do that, you would have to create a bunch of the bands in the circular gradient or stack layers.

Or is that what you meant you already did?

Although you could create on layer and duplicate it and shrink it down... but then the band width would also shrink so that may not work.