Spherical gradient in weight map

mike_f4e16c06

I'm fairly new to DAZ but am learning pretty quickly...

I am trying to create, for fun/learning, a ball with strand-based hair and run dForce on it. (See attached image. The plan is to spin the ball around and see the hair move.) Creating the hair was pretty easy, and I got dForce to run on it, but of course, all the hair just fell off the sphere. So I figured one way to fix that is to create a weight map, setting the dForce strength to 0 at the roots of the hairs and have it sharply increase to 100% a little farther out from the sphere's surface, so the hairs stay in place. There is a brush option in the weight map tool, "Spherical Gradient". I thought I could use it to make a sharp gradient from 0 at the roots to 100% a little farther out from the roots. But it seems that the Spherical Gradient doesn't quite work how I would need it for this. There's a red sphere that defined where 100% weight is, and a yellow sphere that defines where 0% weight is. But it seems that everything inside the red sphere is given 100% weight, even if the yellow sphere is inside it. 

It's also pretty hard to use that gradient. There doesn't seem to be any way to position it to match the center of an object (the hair-bearing sphere in this case) other than "Snap To Bone" which is not quite what I am trying to do here, or to manually move it around and eyeball its location. And I don't see how to move both the red and yellow spheres together so their centers stay aligned.

So the questions are:

1. Is there any way to reverse the gradient when used as a dForce map?

2. Can these gradient spheres be positioned and shaped without having to drag them around on the screen and eyeball their locations?

3. Maybe there's a whole other way to get those hairs to have 0% dForce at their roots?

Thanks.