You can just pinch a taperY channel from any cr2 and paste it into the actors in your own cr2. An easy way to add a channel to all the actors in a file is to do a global search and replace of;

        channels
                {
with;
 
channels
                {
[new channel]



Here is what a taperY channel looks like:

                taperY taper
                        {
                        name taperY
                        initValue 0
                        hidden 0
                        forceLimits 0
                        min -100000
                        max 100000
                        trackingScale 0.04
                        keys
                                {
                                static  0
                                k  0  0
                                }
                        interpStyleLocked 0
                        }

P.S. you can put taper channels in pp2's as well as cr2's, this is a quick way to make some new primatives.