So, while I had purchased all three stretch series and F1 back at the end of summer, varies crises of moving out of our home of 27 years, starting school and my children's own crises had kept me from making more than even a half hearted attempt at starting, I knew they would still be there when I could come up for air. The gymnastics Bodies instagram account was doing a great job of nagging me. 
I'm 55, female. What finally got me started was seeing where I could end up. I did a short, three day clinical in a long term care facility; suddenly my comically tight forearms, I wake up with numb hands many days, with my wrists completely flexed and my hands in fists, was echoed in seeing people who can no longer open their hands due to contractures. That hip pain that wakes me up in the middle of the night; I've known it was piriformis, psoas, glutes but suddenly I saw the results of trying to ignore it or just take advil every night.
Anyway I'm putting this under middle splits because there is no general split series forum. Yesterday I finished my second week of completing, to the best of my ability, each of the series, middle, front, thoracic stretch and core, lower and upper body, F1. And this morning waiting in line at the coffee shop my hamstrings were just firing away, like there was a tens unit on them, they were actually helping my (always extremely tight) quads to hold me up and as I walked home I could feel my pelvis just wasn't tipped as far forward as it has chronically been, and my hamstrings were contracting away. It was simply amazing! I know I still have so far to go; particularly that I need to get the handstand series to get working on my wrists but I was not expecting something so dramatic so quickly.
Thank You for these programs and this forum.