How do you disable the usegravity for a ragdoll and specific childbones with a script?

I am making a character controller with a ragdoll. I thought this could be the perfect way to make a character controller with a skeleton, and not a capsule, so far it works, but I need to disable the gravity of each bone of the ragdoll to add a general gravity for all the armature. I know how to do all of this. But I dont know a script that disables specific bones or all of the armatures gravity component. Bit remember, I dont want it to be kinematic. I want it to remain non kinematic. I have done it manually and it works, but it will be more awesome if I could disable it with a script, i could do wonders.

Here is a video of what I have done so far, I just need to add the animations, the Ik and disable gravity.

video

Please help.