Imo Iron triangle should have the superior Navy. France alone won’t be able to blockade Germany like in WW1, not like the Brits would let them anyway. That being said Italy has a lot of coastline. And the majority of France’s heavy units should be concentrated in the Med. if France was rational the main objective would be to knock out Italy first and reach a status quo ante with the Germans. Without Russia the strategic situation for France is very not good