Yeah - looks like you know what to expect. I've got a 45 bar on 20 lines for strong conditions and so far only put my 10m on it and it's very quick & very fun. As you guessed you come down quicker but probably better off asking someone else when it comes to jumps because I've only just started attempting them with more failure than success at this stage - I'm still sore as I write this but I'm sure that spectators would be amused at my lack of timing.

So does this mean if i increase my line length on my 9.3 warrior for the lighter days i will have a larger wind window hence larger and longer power strokes?

yes wrex, you have a larger wind window, the kite flies at the same speed but will stay longer in the planing zone because it has physically further to fly before it gets to the edge - but it will only give you a 1-2 knot increase in the lower end of your wind range IMO.

Yes wind does increase with altitude, this is due to the friction on the surface slowing the air flow down. Longer lines will not make that much difference in most cases, particularly if you are trying to go upwind you will have your kite low to the side in any case.

There is also an effect that you describe when the wind is deflected up over trees, sand dunes, buildings, etc. Low directly in front is the "dead zone" you mentioned, but more dangerously the airflow is often deflected upward then compresses with the air flowing straight over the top of the barrier - if your kite is flown in either of these zones you can get lofted very easily, especially in stronger winds.

The vertical "ridge lift" is what hang gliders and paragliders try and stay in, but if they drift too far over into the compression zone the increased wind speed can blow them over the back of the ridge into the turbulence behind it - NOT fun and bloody dangerous!

Remember if the wind speed doubles, you get four times the lift. So even in light winds you can get caught out with ridge lift even with small dunes, etc.

This is one of the reasons I had to set the JZ on the Gravity Games so far out and why we had the launch area to the South - we couldn't risk competitors on suicide leashes getting a kite caught in the ridge lift - not to mention all the shallow reef directly downwind :-( It was interesting to note that study also found a significant increase in accidents during competitions.