A rather odd German armored cruiser

I have this pencil sketch with a few notes from the early 1970's for a German armored cruiser. There is a detailed armor plan and some armament notes. The rest, I have supplied through my estimates of what is reasonable. The main feature is the 6-12in guns in triple turrets, one at each end. The secondary armament is in casemates, amidships. They are under the forecastle deck. There are two funnels. The maximum armor thickness is 8in but the majority of the vertical armor is 4in. It seems a fairly reasonable design, except it may be too slow, although I adjusted the design to achieve 26 knots. This is the Springsharp report:

Ger/CA/1909, Germany Armored Cruiser laid down 1909

Displacement:
 15,440 t light; 16,065 t standard; 17,500 t normal; 18,648 t full load

Dimensions: Length overall / water x beam x draught
 550.00 ft / 550.00 ft x 82.00 ft x 25.00 ft (normal load)
 167.64 m / 167.64 m x 24.99 m  x 7.62 m

Armament:
      6 - 12.00" / 305 mm guns (2x3 guns), 864.00lbs / 391.90kg shells, 1909 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      8 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1909 Model
   Quick firing guns in casemate mounts 
   on side, all amidships
   8 guns in hull casemates - Limited use in heavy seas
 Weight of broadside 6,048 lbs / 2,743 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 8.00" / 203 mm 250.00 ft / 76.20 m 9.00 ft / 2.74 m
 Ends: 4.00" / 102 mm 300.00 ft / 91.44 m 9.00 ft / 2.74 m
 Upper: 4.00" / 102 mm 380.00 ft / 115.82 m 8.00 ft / 2.44 m
   Main Belt covers 70 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.50" / 38 mm 380.00 ft / 115.82 m 24.00 ft / 7.32 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 8.00" / 203 mm 4.00" / 102 mm  8.00" / 203 mm

   - Armour deck: 3.00" / 76 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 57,405 shp / 42,824 Kw = 26.00 kts
 Range 4,500nm at 15.00 kts
 Bunker at max displacement = 2,583 tons

Complement:
 759 - 988

Cost:
 £1.541 million / $6.163 million

Distribution of weights at normal displacement:
 Armament: 756 tons, 4.3 %
 Armour: 4,886 tons, 27.9 %
    - Belts: 1,771 tons, 10.1 %
    - Torpedo bulkhead: 506 tons, 2.9 %
    - Armament: 873 tons, 5.0 %
    - Armour Deck: 1,736 tons, 9.9 %
    - Conning Tower: 0 tons, 0.0 %
 Machinery: 2,609 tons, 14.9 %
 Hull, fittings & equipment: 7,189 tons, 41.1 %
 Fuel, ammunition & stores: 2,060 tons, 11.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   27,544 lbs / 12,494 Kg = 31.9 x 12.0 " / 305 mm shells or 4.1 torpedoes
 Stability (Unstable if below 1.00): 1.16
 Metacentric height 4.9 ft / 1.5 m
 Roll period: 15.6 seconds
 Steadiness - As gun platform (Average = 50 %): 77 %
   - Recoil effect (Restricted arc if above 1.00): 0.72
 Seaboat quality  (Average = 1.00): 1.54

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.543
 Length to Beam Ratio: 6.71 : 1
 'Natural speed' for length: 23.45 kts
 Power going to wave formation at top speed: 54 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -1.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  31.00 ft / 9.45 m
    - Forecastle (20 %): 29.00 ft / 8.84 m
    - Mid (67 %):  29.00 ft / 8.84 m (21.00 ft / 6.40 m aft of break)
    - Quarterdeck (15 %): 21.00 ft / 6.40 m
    - Stern:  21.00 ft / 6.40 m
    - Average freeboard: 26.52 ft / 8.08 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 106.9 %
  - Above water (accommodation/working, high = better): 210.2 %
 Waterplane Area: 31,276 Square feet or 2,906 Square metres
 Displacement factor (Displacement / loading): 108 %
 Structure weight / hull surface area: 149 lbs/sq ft or 726 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.90
  - Longitudinal: 2.45
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather