Swirl vase overhang test

I have create this simple vase  with the idea to check the limits of overhang without supports and the adhesion between layes in this condition for my printer.

The model start with aggressive angle almost  30°.

My printer pass the test but  obviously with some imperfection probably 7/10 is the rate.

The result is that now I know the limit for design my models if the use of  support is impossible.