Einar, Here we go
! Here's some pictures that will help. First is my set up with the square, centered on the grill mounting holes. Then a couple of pictures of the measuring set up. Though it does not show clearly in the photo, when the square touched the top hole, the bottom edge of the lip for the grill was 33 mm away from the square.
Next the seam of the sill or rocker panel on which the trim is centered is level using a carpenters level. It is a straight line from the front fender, under the door to the back. Notice the bottom of the door sill is level with the trim and about 5 mm lower.
More in my next post.