You need nukin wind, a decent release off the water, a fast(turning and through the window) kite. There are actually only a few kites that can do it without pounding your ass. I use a Royal Era but the other good ones are Torch, Fuel, Vegas then a few bridle kites like the bandit, obsession. Some kites may feel like they can turn fast enough but what your looking for is acceleration after it comes through the loop. If the kite is slow in that respect your gonna eat it if you go big.
If you don't get the catch on your way down your prolly gonna think twice before ever trying it again. The small ones and the giant loops are the safest. Its the 10-20 foot high ones that kill you.
I would not use short lines to start with(under 20). Work down in line length later when you get bored and figured out the technique. I've had way more go wrong with 10-15m lines than when I was riding 20m. If you ever managed to go above your kite you'll realize why I don't advise short lines until later.
Have fun and remember to have someone take some video.