"A few minor knee twinges" may or may not be related to the crank length, but interesting you say this occurs only on the longer cranks? I have read several things in the last few years that suggest "standard" OEM cranks might be too long for people. Here is one such article:
https://bicyclist.xyz/regulars/ask-t...ing-crankarms/
I did replace my wife's crank, dropping from 170 to 165 and she says it has helped her knees a lot. I'm 73-1/2" with slightly shorter legs than you, both my bikes (58/59cm frames) came with 175s, I've not had any issues.