The reason why the Queen Elizabeths were termed super Dreadnoughts had nothing to do with super firing turrets whatever that means ? Do you mean super imposed ie one behind and above the other ? The reason was the increase in gun calibre from 13.5" to 15" and the increase in speed from 21 knots to 25 due to the introduction of oil fired rather than coal boilers.I hope this helps.
I thought even the battleships with 13.5" rifles (like Iron Duke) were even referred to as Super-Dreadnoughts and by the time the QEs came along they just dropped using these terms altogether especially since even the early dreadnoughts were obsolete. The increase in rifle diameter might not seem that large, but the displacement grew from just over 10,000 tons to well over twice that, hence "super".