Harness materials and such

What type of materials do you guys use, and how the hell do you get them to "Lay" flat?
-Tim

For racing harnesses I use masking tape or medical tape (for strapping ankles and the like). They sit flat because they are still sticky on the back. If that is not enough, they can be helped by some very small daubs of superglue, but not too much or you'll get "frosting".

On road cars I imagine ribbon might be better since the belt is usually just hanging from the reel. For the buckles and hardware there is quite a range of PE sets on the market.