Maintaining what would appear to be a correct flow angle around the mast to the mainsail is of little concern when you are using a Kite. what really matters is keeping the mast in one piece. A wing mast such as superwing is more critical but even on the Tornado we rotate the mast to at least 90 deg when we go downhill particularly if we are on the wire. if you don't then you will have some seriously ugly bend.
Robi, I am not sure how windy you are planning on sailing with the kite but if you go out in 20kts you will bust the rig if you don't rotate the mast to at least 90 deg.

have a look at this pic: Taipan with kite

Or this: Tornado

and this: Nacra F18

Now all these pics are taken in light breeze, the only reason some masts are not rotated more is that there is not enough pressure on the main to force more rotation. You will find that the mast rotation control is loose allowing the mast to rotate as far as it wants.