I always struggled with high mawashi and yoko geri's, I spent years try to stretch trying new methods and programs. More I stretched lower I could kick, later on I found that my hips are not design to kick high. No matter how much I would stretch it won't happen. As I become personal trainer with the postural focus I discovered mobility approach, which helped me to kick higher without pain (like 10cm). What is your focus? Flexibility or mobility or you do both?