I’m afraid I simply take the easier option and go with my 3 to 3.5” chunky heeled boots - although to be fair ease is only part of the reason. I genuinely prefer my chunky heeled boots - aesthetically, speaking and in terms of my own personal style. They seem more “me” if you know what I mean.
That said I really do love the lines of 120 stiletto boots and keep meaning to put in the effort to learn to wear them
It's a matter of practice. I'm a U.S. women's 10 to 11, depending on make and style. I rarely wear under 120mm or over 140mm. My sweetspot is 130mm. These numbers are all based on single soles. I agree that for my size 120 to 140mm also look the best. Anything higher looks off and anything lower just don't appeal to me.
I have a pair of 120mm knee boots from Italian Heels, who scale their heels according to size to keep the lines and proportions correct - so at my size (their standard is a 38) my heels are somewhat higher than 120. I love the elegant lines on boots at this height (but no higher) but don’t get nearly enough practice in them to walk well - indeed do much more than totter.