Thank you, this picture help me a bit.

I always test the position of the parts like you're doing in the picture, too. At least with 1590A enclosure. With bigger enclosure just if there are a lot of thing inside.
I will buy a cheaper equivalent. I could but the 51x51mm, but there's another slightly bigger, 60x55, unfortunately the height is 30mm, not 32mm.
Probably I can draw a layout after I have bought one of these enclosures.