I really wish that there was more research/allowance for how rider body type (and horse body type) affect the combination’s ideal position. Eventing isn’t as bad as hunter-jumper, thank God, but I’m sure many of us started out with hunter-jumper lessons, and it was drilled into me that it was always the fact I wasn’t “strong enough” to “hold my body in the right position” when I now realize I was just shorter legged and longer torso-ed than the “ideal rider body type.” A rider can adjust strength/flexibility/softness/tension but adults cannot magically grow shorter or taller, and using the wrong saddle or stirrup length for your body on the horse, for the discipline, will just make everyone miserable.
I mentioned this in the other thread, but for awhile it seemed like there was a fad for many eventers to ride dressage at William Fox-Pitt-length stirrups without being WFP tall. Like, many people in the dressage riding with their boots barely brushing the stirrups. People seemed to be riding a bit shorter this year, and it seemed to work well.