Everything so far sounds right to me. But...

Isn't it best to have the widest possible range of gears for both speed on the flat and climbing ability (given appropriate terrain, unlike here in North Holland )? And if so, won't the commercially available gearsets offer that only with the largest set of combinations, achievable with a 3x10 setup (though I would leave ten speed out simply because of cost)?

There could be more duplications, but possibly a broader range with smaller increments as well.

I think a pencil and paper have made their need felt.

Cheers...Gary