Hi Mr-NYM,
for the zip I used a technique shown in the dvd from Gnomon, “Introduction to character modeling”.
You build the zip by placing many tiny pieces one next to the other, like a real one;
then combine the mesh and create a joint chain as long as the zip, with a joint for each piece;
then apply a rigid bind skin;
then an Ik spline handle tool.
If you have a curve un your model you can attach the Ik handle to that and you’ll have the entire chain snapped to the curve. And with the control vertex you can tune the placement.