I want to create a radial gradient, with 3 stops, on a series of objects. Each object however is a different color. How can I simply switch the gradient to be a different color? I don't want to have to modify all the stops on each copied gradient individually.

Okay, maybe I figured out something. Instead of using gradients I can use the masking tool. I create an object and a mask object (grayscale). I then apply the mask. This lets me copy this object and quickly change the color and still have the mask apply.

Is this a good approach? Are there other ones?

Hi.

Are you after to add different colours to steps set in gradients in different object's fills easily?
You can try the tweak tool.
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Tweak-Colors.html