I tied front to back, and side to side all the way across. I was too lazy to do diagonals. If you search on the googlemachine, you'll find upholstry articles showing this, and what knot to tie. And pictures!!!!
As these seats are already the right "shape" all you are trying to do, is make more than one spring move at once. What you want, is the opposite of Christine Mcgee's pocket coil mattresses. When a spring gets loaded, you want it to drag down all its spring friends around it. Thus firming the seat up, and tending to make it less bumpy.
