Hope you don't mind a long ramble but,
with a crew of 1400-1800 there are no manning problem at all
My idea was that you cut crew number to cut costs/weight.
If we assume that crew wise you need,
6' twin crew = 42 (from 6"/47DP Mark 16, Manning was twenty-one crewmembers in the gunhouse, ten in the turret officer’s booth and eleven in the gun house)(212 mt)
This gives you x4 for a 168 crew and 848t for your main guns that are a good pick IMO
Then we get complicated secondary AA guns
- 14 x 57mm single (why not twin ? you can only point at as many targets as you have directors anyway ?)
cant find a single weight or crew but twin Sweden 57 mm/60Model 1950: 23 tons (24 mt)(crew ? assume 10-15 for twin ? so maybe 8-10 for single ? with weight of 14t ?)
- 12 x 40mm twin crew = 11 (5 + 6 ammo ?) (USN For twin and quad mounts, the crew consisted of a Mount Captain, Pointer, Trainer, a 1st Loader for each gun and then however many ammunition passers it took to get back to the ammunition supply point. In addition to the guncrew, there was normally a Mark 51 (or later) Director crew consisting of a Pointer and a Range Setter.)
weight (4445 - 5897 kg)
- 8 x 20mm twin crew = 5 ? (Mark 24: 1,400 lbs. (635 kg))
Why not a 3' twin unless you don't have assesses to VT shells ? RN 3/70' twin 12 crew (37,716 kg)
- your option gives a total crew of (14x10+12x11+8x5) =
312 men and (14x14+12x5+8x.6) weight =
260.8t
a uniform 3'/70 (260.8/37.7= 6.9) so you might well get 7 (or 8) twins (with the reduction in structural weight and directors) this would only need 7x12 = 84 men (or 96 for 8 twins)
saving over 216 men (more due to directors etc) (and that will add up to saving in all other departments that support them).
IMO a 8x 3'/70 would be much better (if you have VT shells)(as it should be as both USN/RN picked that option post war !)
If you don't have them VT then a full 57mm is next best IMO, this is not even taking into account that the 20 (and really the 40 as well) are mostly obsolete and to short range to help much.