Those four frictions are probably grooved as well. You'll be losing about 25% strength by using four grooved instead of five smooth. I have actually measured and computed the friction surface area lost with grooves. But this is what they package; and act like this is the accepted practice for performance. Like I keep saying; there is no kit available; you have to buy separate components. Sometimes I'm sent thick or grooved Red Eagles for 904s and 727s. I send them back. OEM plates are thick and grooved because they can't take the heat otherwise. "High performance" kits should have five smooth thins with an extra steel in them.
