The side window patterns have been filed to fit the aperture, then been reduced by 20 thou. all round to clear the window moulding material. There is a bar of 0.3mm wire set in to a groove so that the very fine glazing bar has a slight witness line in the vac-forming.
Here are the two patterns side by side.
The V grooves are there to help the vacuum reach the detailed parts. It also helps stop "webbing" on forming.
Next the front and rear screens and then the finishing.