Three degrees in the center and less at the wingtips should be fine.
Regarding the cell count there is a very big difference between foil kites (and paragliders) and tube kites. They don't need ribs to shape the profile and keep the thickness constant.
But having a very low panel count on a tube kite causes wrinkles in the sail because in the air you will have a round shaped trailing edge and "corners" in the leading edge.
You get a clean sail without wrinkles by either increasing the number of panels or adding spanwise konvex seams.
Changing the panel count is very easy with my software. It's just a parameter but it rapidly increases the amount of work.
To get a round sail shape I added konvex spanwize seams . Easier to sew and they have almost the same effect.
I will add an option to create and unfold a "constant curve" leading edge to my software. Never really thought about that but I like the idea. Thanks Mr. Hansen!
I will also publish a new version of the Ventus
with a higher number of panels within the next days. And also a 10sqm version of the Agilus.