D.K. Brown on battlecruisers

Several years ago, I had some communication with David K. Brown, the retired naval constructor and author. My understanding is that he thinks that battlecruises with light side armor are acceptable (with "splinter protection") if the "vitals" are sufficiently protected. That is really the modern protection design pattern. I think that he would prefer at least 6inch side armor, if it could be had, for a battle cruiser. What really needs to be protected are the magazines. I would add that something besides Cordite should be used as your gun propellant, as well. Nitrocellulose would seem to be a good candidate. Cordite is BAD, and should be avoided at all costs. Four British battlecruisers, as well as other ships, were lost due to the use of Cordite. The problem was not the lack of armor, but the unstable propellant in use. As Admiral Fisher would say "armor is vision", so more armor is not that bad, if you can provide a good speed and a heavy armament. Ships like the Derfflinger were good, but needed something larger than 12inch guns.