I dont understand why it goes "out of control"???
I dont have the 633 but a similar sized surf wing (1200 cm2), and never experience it being out of control, nor seeking "up"
Do you have the straps set "neutral", or strapless where it doesn't matter?
Maybe the default rear stab angle needs a little shimming?
Or are you sometimes riding extremely powered at higher speeds, thus it gets "bouncy"?
Quite odd I dont experience the same, so I dont have to put more weight on the front foot at higher speeds, so could be a matter of trim simply, of the rear stab?
The reason I, like said in the other thread, often use the big wave wings instead of the huge surf wings, is simply because they feel good giving more speed without kitepower in turns and waves.
And sometimes in bigger waves I want low speed and max control not getting the "too much speed bugger" situation, and will go with the surf wing