Unsure if this has already been spoken of, so forgive me if this is already on the table.
What about removing barbettes and instead letting players adjust a guns height individually with a cost of X in weight per inch (or another unit of measurement) with an auto made barbette? Could even have the Value of X be relative to the gun size. Allowing only max heights relative to hull placement, disallowing a triple high far bow mount for example yet allowing for a double or triple mount near center-lines on the hull/bridge.