man, i am so not flexible, its almost not funny anymore. with straight knees and the feet together, there are somewhat 5-7 inches missing when i try to touch the floor.
but i can easily do both mutes, tails, high criticals, dub japans, dub criticals and even octos. just start with mutes, i find them the easiest grabs (you just have to find out whether you think its more comfortable to pull in or against the spin direction). just relax and dont grab too fast. set the spin, do the first 90 or so and then grab, because if you start too early, it will throw you off-axis.