Using spacer between bucket seat & side mounts
 

I have a sparco pro2000 with universal sparco side mounts and am using the stock sliders to bolt to the floor. When i have the mounts attached to the sliders the seat is too narrow and there is a 3/8 inch gap between the seat and side mount on both sides.

Would it be safe to use nylon spacers in between? I could always try drilling the holes on the side mounts wider for more adjustment but dont no if there is a tool more effective at doing this than a regular power drill/dremel.