Sounds like you're doing ok, don't like the sound of your preinflating method though, try sanding the trailing edge and preinflating by opening the butt plug while you sort out the lines.
In light wind don't try to park it low at the edge of the window or the first lull will have it, like any kite.
In really light wind keep it moving so it always has apparent wind and flies through the lulls.
It's not a scary kite if you use it in light constant wind, it's great, you'll love it.
I used to launch my ARC's down wind with no problem. I would drag 20 feet or so ocassionally. The trick with ARC's was to keep the kite stalled and it would climb only a few feet at a time--a real slow ascent. Then I learnned to launch the ARC from the side. It should work for the Flysurfers too. Put the kite downwind as you would for a downwind launch. But hold a tip and let it streamer downwind. Then lay the kite down and sand the upwind tip. Stand directly up wind and back up until a tip comes up. Hold it in that position until it inflates and then back up until the kite flys. But keep the same steering angle and it will fly to the side of the window instead of straight up. When at the side, you can then fly up. Also, if you want the downwind drag, as soon as the kite starts to lift, drop down on your but and depower the kite and it will rush to the top and drag you for only a short distance.
the mast air is nothing like the psycho at all, it has 1/4 of the depower ramge and about 15% more low end.
if you haven't tried it.......
Okay - but the principle should be the same, should'nt it ?
I remember my good old Windtools Mosquitos - when starting in real high wind, there was no problem - if you just started "uninflated".
It simply does not power up that much, or accelerate. Easy.
Launching the mastairs downwind is fine unless it is really strong & then you should follow Jo's advice. The method I use for downwind launches goes along the lines of what the arc thread said.
Make sure the kite is at least 50% inflated (open the bumflap while undoing your lines. The mastairs can do strange things when not inflated. Hook in. Yes I know this is scary but not so bad if you use a good snapshackle or one of the new, safe chicken loops. After you are attached, keep the kite fully powered up and step back to remove the sand. The kite will sit on the TE. Before it gets much fuller depower it only until it rises of the sand. The kite generates pull through speed so control the speed by keeping it as powered up as possible without it stalling. When it is 1-2m off the ground, turn the kite to the edge of the window. Having the kite powered up makes this easier. When it is near the edge, then depower so it pulls less.
Looking forward to hearing about your progress. BTW, if you bought your kite SH then check that you have a current model bar. The original bars have a brass sleeve around the depower loop and they snap. the current sleeves are aluminium. FS should replace the old bar for you.