A serpentine front is not six curved doors. It is one curve that happens to be cut into six pieces, and that distinction is the whole job.
Each door here is shaped from thick solid stock rather than bent, so its curve is cut and not forced. The temptation at that point is to shape each door to its own drawing and hang them in a row. Do that and the front becomes a series of separate bows: every joint between doors shows a small change of direction, and the sweep the design is after never appears.
So our master Indian artisans strike the whole front as a single line first, full size on the floor, and take every door's curve off that one line. Where a door ends, the next begins on exactly the tangent the first left off at. The cornice above and the plinth below are shaped from the same drawing, which is why they run continuously across the piece instead of stepping.
The test is done with the doors closed and a hand, not an eye. Run a palm slowly across the whole front: if you can feel where one door ends and the next begins, the line is not right yet.