Sorry, file is nc now but yeah just doing the calculation in sops on the point color works.
Attachments in this post:
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20263205/02/26/image.png
http://fx-td.com/houdiniandchill/wp-content/uploads/discord/20263205/02/26/rainbowMotionBlur.hipnc