Don't be afraid of ngones and tris on a flat surface, it will not deform bad or show bad shading, it's another thing if this would deform. Does it subdivide good?
That surface is non-planar (not flat) hence the visual artefact (pinching) result. Try FrankPolygon's third *ngon* example and see if it makes any difference.
I'm trying to make a hill with a flat path spiralling up it. This is just a modelling exercise but i've hit an issue. I made a sphere and squashed it into a round hill shape, I joined that to a plane and chamfered it. So I'm now trying to add the path. a few things i've tried is using a helix and making it into a spline.…
Thanks a lot! I thought about something along these lines (creating it flat & bending) but I couldn't picture it properly in my head. That helped a lot!