Kongo Replacement Design 20K Variants

By the time of the first London Naval Treaty of 1930 the previous Washington treaty's Battleship building prohibition was coming to an end and both the USN, RN and IJN preparing various battleship designs ranging from 20.000tons to 35.000tons and armaments of 10" to 16". United Kingdom wished for a small displacement limit so it could maintain numbers as well as not to escalate another arms race with larger and larger gun calibres meaning battleship sizes and eventually costs. While the Royal Navy could not produce a battleship design on 20.000tons and either 10", 11" or 12" main weaponry, Yuzuru Hiraga, the prominent naval architect of the Imperial Japanese Navy drawn up 2 designs on this displacement limit, one with 3x3 30cm cannons, the other with 2x3 36cm ones.
As there are no other info available apart from displacement and main armament I had to use the final 35.000ton version as a basis for this design and make it smaller but otherwise very similar looking ship.

The design had the following characteristics:
Dimensions: unknown (I've used these: 185 (wl) 187,5 (oa) x 28 m )
Displacement: 20.000tons (standard)
Armour: unknown probably, around 229mm Belt and 127mm Deck
Engines: probably around 60.000shp, 3-4 shafts
Speed: 46km/h (25knots)
Armaments:
3x3 305mm/50 Type 90 Cannons
2x2,12x1 140mm/55 Type 88 Guns (No info on actual number and layout)
4x2 12cm/45 10th Year Type DP-AA Guns
4x1 40mm Type HI AA guns (I've added it to the design)
2x1 61cm Underwater Torpedo Tubes
2-3x Seaplanes (Nakajima E4N)

Variant B was a different armed version of the 20.000ton design proposed by Yuzuru Hiraga. While on the "A" design superior firepower achieved by mounting more numerous guns of 30cm calibre, on this proposal the main calibre was risen to 36cm but due to weight constraints of only 20.000tons, their number was reduced to only 6 cannons in two triple turrets, even with only two turrets the armour probably had to be reduced somewhat, otherwise very similar to the first, A design.

The design had the following characteristics:
Dimensions: unknown (I've used these: 185 (wl) 187,5 (oa) x 28 m )
Displacement: 20.000tons (standard)
Armour: unknown probably, around 278mm Belt and 127mm Deck
Engines: around 60.000shp, 3-4 shafts
Speed: 48km/h (26knots)
Armaments:
2x3 356mm/50 Type 90 Cannons
2x2,12x1 140mm/55 Type 88 Guns (No info on actual number and layout)
4x2 12cm/45 10th Year Type DP-AA Guns
4x1 40mm Type HI AA guns (I've added it to the design)
2x1 61cm Underwater Torpedo Tubes
2-3x Seaplanes (Nakajima E4N)

The various proposals can be found in this list:
http://gazo.dl.itc.u-tokyo.ac.jp/hiraga2/show/id/20680101#?c=0&m=0&s=0&cv=0&xywh=1706%2C220%2C969%2C1682&r=270

Barbette and turret drawing for the 30cm/50 Cannons
https://iiif.dl.itc.u-tokyo.ac.jp/repo/s/hiraga/document/7320ab46-a21c-4fdf-ae5f-8ba46413371b#?c=0&m=0&s=0&cv=0&xywh=169%2C404%2C6318%2C2851

My suggestion for names of these ships are:
IJN Iwami IJN Higo
IJN Sagami IJN Suwo