Well, it's a bit long but I think it's a very good review. Haven't read
Castles yet but have recently been inspired to: reading Keegan's
Price of Admiralty right now and am actually in the middle of the part that deals with Jutland. The only suggestion I might have is that you avoid saying that the High Seas Fleet was unwilling to risk its ships. I see your point, but IMO it implies that the Germans were afraid to fight. They were quite willing to risk their ships, based on "risk theory" - the idea that their fleet could absorb a great deal of punishment if it could mete out a great deal in return. Tirpitz and others rationalized this by believing that German seamanship would prove superior to British when the crucial time came ("the day" as they called it). However, for reasons which I am still learning from Keegan, they avoided many opportunities to risk it in an effort to seize "just the right moment," so to speak. In other words, it's not that they shunned Mahan's decisive battle; they sought it eagerly (Entscheidungsschlacht), they were just really choosy about finding the most favorable conditions under which to fight.
But this is a quibble. I think it's a very good review; certainly a positive factor in my considering buying the book.
