No, the spanish american wars do count...as points for me. The average battle was less than 5 gunships per side. As also do the Latin American wars, "Sino-anything wars" and the Danish-Prussian Wars, and the Battle of Helgoland. Some isolated battles during these wars had up to 10 ships per side.
Navarino was big but was hopelessly one sided. Sinope was about 10 per side.
In WWI we have another Helgoland, but as I said about Jutland, this is at the end of the period. As it is causing concern, I will clarify by adding I dont think WWI should have been in Vicky1. It was too much of a stretch with the one tactical resolver for battles.
I will withdraw post Trafalgar, because what I meant to say was post Napoleonic and pre WWI. You list Athos, Dardanelles, Lake Erie, and Lissa which were all during the Napoleonic wars but were hardly of importance compared to Trafalgar.
You are correct when you say "In fact most wars of the period involved naval actions," but I never said there were no naval battles. Simply from the point of view of grand strategy, they could be represented in a game (not historically simulated) by EIC in a Vicky2.
IMO, to be a naval battle of a "very significant scale", it should have large fleets and a contestable outcome. One of those you mentioned counts - the Russo-Japanese naval engagement - and then it only counts in theory. In practice it was heavily onesided and can be ignored for the purposes of a game.
So there were only two well within the specified timeframe. The Russo-Japanese war (which I would right off in Vicky2 along with WWI and stick to colonial wars, as the name suggests) and Navarino, a battle where something like 20 western ships beat 4 times their number, and most of these were small ships. Neither of these two can be said to be a good fight that would make an enjoyable game.