Hoi John
I am sure it's going to be a ripping model!
What I meant by detaching was, for example you could make your basic box with as many patches as you think you need, then manipulate the box into a basic car shape with the deformer box, then for the windshield (which is always nasty :) ) cut and copy, destroy the original wind shield on you box, move your new one in and place it a little back (or deeper than the original), correct the mags and biases of the splines cause now they are broken. Select the windshield hole edges on your chassis, extrude and move them into the model for depth (correct these too), and you will have a continuation of shape with a sudden change in direction, only the windshield is floating but you have that nice edge detail. You are actually starting with a basic shape and altering the panel depths, manipulating mag and spline biases lets you keep shape integrity.
Probably more info than you wanted but I came up against it myself. Lately been doing quite a bit of product design and visualization in AM and the Reynolds link got me out of hot water more than once!
Kind regards,