I must just have weird femur leg lengths.

I'm 5'1, I use a set back seatpost with my seat all the way back and can get comfortable leg wise on a 73 degree seat angle. 73.5-75 degree seat angles, even with the setback & the seat all the way back, my legs are just not in the right position. I don't use WSD's because I find the top tubes too short - so my top tubes usually about 540 mm with a 100 mm 6 degree stem & standard reach handlebars. I usually use about a 48 cm frame.