mouse trackball speed

Hi, I am running Zorin 7, on a Acer laptop. I recently changed to a trackball (generic brand), and it is just a little to sensitive. The speed going across the screen is fine, but trying to make small movements such as clicking on a link or closing a window is hard. I have some medical problems and using the trackball is more comfortable than a mouse, but my hands shake making the problem worse.
I have tried xinput, xset, downloading gconf (this version does not even have a setting for the mouse), I downloaded another mouse setting program, don't remember the name of it, it did nothing.
This is not a serious issue, it is just very annoying and would be great if I could adjust it. Any ideas will be appreciated.