Tell us more about the rig.
One thing I can say as a suggestion, you might want to put some weight on the rig so that the sliding is smoother and less jerky.
Just a test video of my cheapo camera slide that I just built. Filmed with a go pro and thrown together quickly in premiere. I need a video capable dslr bad
I feel that the weight isnt really an issue. The reason for the jerks are that it isnt 100% smooth yet since the track is metal and the actual slider is metal too; so its pretty much just scraping. I need to figure out a way to lessen up the friction. Its not bad if you slide fast, but slow sliding makes it prone to sticking. I have tape on the track surface right now so it helps a little. Once i can figure out a way to smoothen out the surface, then I can use a bungee cord or rubber band to get more fluid movement