FACTS are what actually has HAPPENED! I can't explain it much simpler to you than that!
Why would you ASSume, I remember some story about an ORANGE, when I NEVER heard it?
I guess that's your version of "facts".
Until you have experimented with different length cranks AND the subtle gear changes appropriate to those different length cranks, you are simply guessing about what the best length is!
I've made up a custom cassette from 2 different cassettes. Thus I have the ability to fine tune my gear ratios VS crank length. I've probably made 4-5 minor changes to get the cassette dialed in for MY riding. That will probably change in the Winter, when it's colder & windier.
So far, I've used 175, 170 & 160MM cranks.
The 175's are definitely too long for my bad knee, as explain in the original post.
I'm
slightly faster on the 160's than the 170's, but they seem to feel a bit too short. I hoping some 165's get left on my doorstep by the crank fairy. Then I can wonder if 162.5 or 167.5 is better
Budget constraints prevent me from buying some. (My 160's were $7.50 +S&H)