Unlike real-life, there were no naval treaties that limited the building of capital ships (WNT) or the size of cruisers (LNT). It makes no sense to limit the gun type if your enemies are still building battle cruisers.
In fact, I think Barao should increase armour limits bc you can make a 16k tonne CA with a lot of displacement left over. If he could increase the armour limits, it can be proof against 'cruiser-killer' battlecruisers and escape.