Radius compensation - Z axis

Good morning all. I have a problem that I just can't seem to get my head
around.

I think I understand radius compensation in the X and Y axis but not in the
Z axis. I'm using a ball nose mill (.750) to mill a curved track in either
the XZ, YZ, or XYZ plane. There are six of these tracks around a center so
2 of them use 2 axes but 4 of them use 3 axes simultaneously

I thought about just programming the spherical center-point of the ball
nose to cut a radius that is .375 smaller than what I need, but I'm not
sure if that's the best plan.

I'm worried that radius compensation would do nothing more than move the
groove in only one axis, i.e. if I use a radius compensation on a G02 or
G03 in the XZ plane, would the groove be moved in the X axis by the
compensation amount or would the radius of the G02 or G03 be increased by
the compensation amount?

I guess what I really need is spherical compensation instead of radius
compensation.

I'm using a horizontal machine if it makes any difference.

Any and all ideas and comments welcome.

Ethan