When I made my other Bento Box quilts several years ago using a different method this is the layout I used, with all of the blocks in the same position, light upper left corners.
I saw a Bento Box on the Internet somewhere in the past that used sashing between the blocks so I spaced them on the design wall to simulate sashing. With both light and dark at the edges of the blocks it may be difficult to choose a sashing fabric.
The other layout I tried is with 4 dark corners together which automatically puts 4 light corners together too. I was so sure I wouldn't like this layout but I think it is my favorite at this point. When I get more blocks sewn I'll have a better idea which layout is best.