well its not that easy when it comes to board
If u have alot of money and just dont care spending em, buy urself such a big board like 148 - it surely will skyrocket ur learning process. But, if u have a chance to rent a big board for first few sessions, buy somethin like 133 (for example Cabrinha Custom, i got it myself, really nice twintip with a "wake" feeling), and just learn on the rented one till u learn going upwind well.
I personally got 9 and 13 Xbow ids. Nice kites, nothing wrong with em, except u need a lot of power in ur arms so it can be a little exhausting (especially that stopper override units is a piece of shit:). For hooked riding, speed, they are the ones to choose. Switchblade needs less power on the bar and is made for riding unhooked (or it was supposed to be so:). Anyway, both kites should suit u great because lets face it, they are not so different designs. Whats great is the IDS function, which, without 5th line, allows you to have benefits of it.
Riding left side (I suppose u are goofy-legged). U live in germany, a lot of wakeboard lifts there. Bring ur kitesurfing board there, unscrew fins and try doing 180 from right leg in front, to both in front to left in front. I suppose thats the best way to learn it, because u dont have to wait for wind, dont have to watch where ur board felt and so on. I strongly recommend that:)
Cheers mate and remember, whichever kite of cabrinha u will get, as a beginner u propably wont feel much of difference:) (when I crash my kites im gonna get SB's next for a try:)