something like this.. it has 2 wheels on it, so in a way, it would keep from binding. one side moving, one stopped, so it'll keep it easy to roll..
the i now need to find the rail for it. and i can modify the brackets so it's more of an L bracket, so i can have some rounded hex head screws on top to hold these rails onto the roof. then at the very back end, have some type of stopper which i can remove so i can easily have access incase i need to remove the ragtop..