[AndyG]

I mean the area of design just in front of the window - you want that to be dead symmetrical naturally.

If you get a piece of paper cut to size to cover the area of the design, then fold the paper along the desired line of symmetry. Then, starting at the folded side, cut a curve or whatever shape you're after, then open up the paper - you will have a perfectly cut symmetrical shape.

You can then hold that down onto the shell using it as a guide to draw on your guidelines.

If you draw it on freehand without a guide, then only a select few uber-artistes will get it perfect.

If you look on my paint thread, the recent shell I did for Steve Kirk, I used this to get it just right where the chrome trim lines came to a "V".