Looking back on it after sleeping on it, it seems like the kind of boat that would most benefit from an internal well-dock would be the small, very fast type of patrol boat, and I can see that something like a missile boat would neither need nor substantially benefit from that, though it would benefit from a mothership. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
Now, I wouldn't use that gun as it's not made anymore and because there is a much better one: the Otobreda 127/64. 127 mm, 25 rounds a minute (good enough!) and a massive 84 km range with standard shells! Even better, the new guided Vulcano shells will reach 120 km, better than many anti-ship missiles!
The only orders for that gun has been from the Italian and German navies for their new "frigates" (read: destroyers) which are both in the 6000 ton range. I wonder how small a ship you could mount it on, if the ship was only supposed to carry the gun (or some other mission module) and nothing else? It is after all dseigned to be a 127/54 but with lighter weight, for corvettes and the Turunmaa class were much smaller than these destroyers will be. Maybe you could even put it on something like the Göteborg class?
The Bofors 120 mm autogun on the Turunmaa class Hamina class fast attack craft. Four Göteborg class The new Otobreda 127/64 lightweight gun Peak oil is not an energy crisis. It is a liquid fuel crisis.