Back when I had push/pull steering, my 4" BDS springs would flex enough that when flexed out and at full crank left, the tires were still pointed a little to the right. Crossover made it so the truck turned perfectly both ways, I didn't even notice a difference with the truck flexed out or not.
BTW, I plan on dropping the suspension ~2" and having significantly more flex than I have now later this spring. Even with the truck only a couple inches over stock I would never be able to run anything other than full hydro or crossover.
I think that crossover is more important on a flexy suspension than a tall one. 8" lift and over shouldn't even consider push/pull steering, IMO.