2 versions are planned : Normal and Long. Both are indentical from the front up to the end of the front door. They akso share the same tail lamp, rear bumper and boot lid. Rear door and rear lateral panel are specific.

At the workshop, the clay mock-up of the Normal version is made first. It will be the Master model. And the Long version will be made later, only in surfacing. It's a bad choice.

The front door is common for the 2 versions. The ab segment induces a very flat shape up to c. Extended up to c', it becomes quite straight.

It would have been better to begin with the long version. Indeed, curving slightly a line is always possible, while there's no way to make it flatter than flat.

As a consequence we must move b outward. The clay model is no longer the reference.

Many years later, in modeling, I had a similar job. To avoid any issue, I worked on the 2 versions in the same time.