In case anyone is still reading this thread, I found a quote by someone who as asked to have their crossguard upgraded to Diamond:
My current setup is a crossguard, and I guess with the diamond they put rbgw on every side of the saber. So when you mix color they all match. Which is pretty awesome and really makes me want to buy this setup.
So it sounds like you can't really stagger the ignition, but you will get the full effect on all blades, which is nice.