top layer in spiral vase

[NinjaAtWork]

Hi all please have a look at the end of this spiral spring in below: https://www.universalcycles.com/images/products/large/81314.jpg

i need to make top layer of spiral vase in clay print to finish smoothly which the last point cant be seen or be find easily . by decreasing both extrusion and fixing the height of last layer to prevent big elephant foot step and make the z height. how this can be done please? thanks