Reading this whole thread again, as I couldn't remember what I'd posted, it occurred to me that threads like this attract posts from folks who are, well, unusual. I mean, most folks just ride their bikes and don't worry about their crank length. During my whole riding life, I think I've talked to one person who was interested in getting a set of different length cranks. He didn't, though. I've been in the "normal folks" bag as far as JRA goes. That said, here are a couple of photos of my wife and I on our tandem. Notice anything unusual?
In both photos my crank length ratio is 22.6% and my wife's is 24%. The first photo is us in winter trim, my wife on bullhorns, me on my clip-ons. That's a slammed -17° stem. In the second photo my wife is on her clip-ons using s setup I built. We rode just fine. You can see that our thigh angles are almost the same. I could get lower by using a -40° stem, but there's really no need. This bike already has the best power/drag ratio one is likely to see. Too bad there's not more power!
Since these photos were taken, I've replaced her crankset with a set which are 22% of inseam. We're still well above Zinn's upper limit. We find that we climbed better when my wife had the 24% cranks, but they did work her leg muscles through too great a range of motion. So the shorter cranks are more comfortable for her, but we're slower. We did a 154 mile 9500' ride with the longer cranks, no problems other than the usual pain. Our team age then was only 134.