Wouldn't it be more accurate to state it depends on angle to axis of viewing? People getting close with their framing have complained about the 20mm - sure standing back would be better - but that's because their subject's extremities would be at a smaller angle to the axis.
Also, you initiate by stating Perspective isn't created by focal length, but by distance, then mention suggestions for focal lengths depending on framing.
In the end it depends on how you want to frame your subject. After a point though extra focal length just seems like a hassle without making much difference.
