Optimum prop pitch vs. gear ratio

[MetricMuscle]

As I do the math and look at all of the many options I'm wondering if there is an optimal gear ratio and prop pitch.
Is there a point where alotta pitch will start to have unwanted side effects?
Is spinning a higher pitch prop more slowly better than spinning a lower pitch prop faster?

[Magcat 62]

IN general a faster spinning prop will slip less being more efficient i read for optimin try to stay as close to 2-1 diameter vs pitch example 14x28 prop basic proping rule small dia big pitch top end big dia low pitch for low end power gear ratio is big part for achieving this concept

[Magcat 62]

first you would need to know at what rpm peak torque and peak horsepower occurs with your engine you would want your cruseing speed to be close to engine peak torque and wide open at peak hp,if you had the time the gears the props you could achieve the perfect combo

[MetricMuscle]

I suppose more info would be helpful.
20' aluminum tunnel/catamaran air entrapment hull.
Surface propeller, torpedo 2" above bottom of hull.

Instead of finding the right spec propeller to work with my engine and gearing combo I figured I'd start the other way around, see if there is a particular combination of prop specs that are the most efficient and/or just work well and then get the proper gearing to work with the prop.

With a few things I've worked with, sometimes the faster a part has to work, the greater any fault or inefficiency becomes, it's better to use a larger part and have it cycle more slowly.

[MetricMuscle]

I did search some before posting this.
Is there a tread someone would be kind enough to link which has discussed this already?