Brassica help please

the sprouts, kale and calebrese grow tall and may shade out the shorter cabbages if you mix em up. I would put the cabbages in front (facing southwestish) with the taller ones behind. Spacing sounds a bit close to me for the taller plants too.

I would grow them in blocks 4 plants with two rows going right down the plot 60 cm apart.
The rows down the plot will make it easy to hoe and to cover with net.
Each row would have

Kale
psb
calabrese
sprouts
caulis
cabbage
 

All spaced at 60cm .

The calabrese will be harvested before the psb and sprouts and can be taken out to give the psb and sprouts more space to grow.