Just came across this vid which, among the fin pimping, has some sweet footage of how fast a top course racer goes.
What's with holding the depower strap in one hand when the bar isn't fixed anyway? Kites don't really need to be trimmed that much in most conditions, particularly hooked in with a reasonable throw on the chicken loop. To me any amount of trimming he is doing with the depower strap he could do with more precision with the bar, it would certainly be hard to be precise working the bar and depower strap at the same time/pointless.
Also, "I think kite and board designs will stabilize, one area which we will continually be able to innovate and improve on is fin foils" LOL could not talk more **** if he tried.
I think using the trimming line allows them to keep a good stance with their weight outboard and therefore hold more power.
Bit of speed on an Aguera slalom board at the end of this clip.
usually they are using a bit bigger kites in racing that you normally would and ride the kites a bit more powered, then you can adjust trim/power of the kite while you riding with your depower strap while keeping the bar pressure point on so kite doesnt loose power when flagging out. works well
I understand what is is doing.
Just like sailing perfect trim makes you go faster. The less you sheet in and out the faster you go.
He is just sheeting in and out with the the depower strap.
We used the same trim style on our F18 catamaran for years before I seen the light. 
For ex-windsurfers, pulling in on your front hand and easing your back hand slightly to to sheet out comes naturally. Perhaps having a relative movement between hands (and he always has the trim in his front hand and bar in his back) is better to keep a stable centre of gravity than having both hands move in as a gust hits. Yes he could keep his front hand out of it altogether, but I'm suspecting he's thought of that too. There seem to be pulleys on the trim so he's got maybe 3:1 power there, hence the long trim line (as well as it letting him keep more outboard).
Who knows, maybe someone who knows Adam could rope him into posting on Seabreeze and enlightening us all?
If you look at the clip from Fuerteventura, you can see the bent over stance the sailors have to adopt to be able to sheet the bar in and out far enough.
Then compare that to Johnny Heineken or Adam Koch who finished first and second in this years world championship, and you can see that the trim line is an extra level in performance - when you can do it well.
The film was made for Rista fins, so that may explain the emphasis on fins. I expect more development on boards, even more development on fins, but I expect that kites are still the area that will develop most for lightwind racing - if there is no cost capping.
