Calling all Royal Sovereign class pre-Dreadnought fans

[Sr. Gopher]

Well, all I really have to ask is: how effective were the main guns in the position they were in? In a barbette, and not a standard turret?

[DariusP]

If, by "standard turret", you mean heavily armored circular structure* (used on HMS Victoria, Sans Pareil, Trafalgar and Nile) than your question was answered in a definitive (but quite expensive) way: under the influence of Sir Arthur Hood one ship of RS class was completed as a turret ship and named after Admiral.
It was not a success... Because of the weight of the turrets Hood had much lower freeboard and her main guns were about 6 feet lower than in the rest of the class. Also due to the reduced freeboard her midships 6 inch guns were of little use and were removed in 1904. Much less seaworthy than the rest of her "sisters", Hood was 1/2 knot slower than RS in calm water but her speed decreased rapidly in moderate and rough waters. Finally, and here is your answer in a nutshell, she was the last low freeboard turret ship of the Royal Navy.

* What we call "turret" today (and was called "shield" or "gunhouse" at the end of XIX century) was introduced on HMS Centurion and Barfleur.