Here are 2 types of staircases. They are tileable vertically. Just need to rotate them 90 or 180 degrees. You could have multiple floors or just 2 floors. I finally decided to go with a white and red combination. One is compact and 2 are wide. The wide ones are the same, but with 1 difference. a wall on the outer edge.
I placed a single block in center of the wide ones so that you can easily tile it. When you have placed it, you can easily remove the block after.
Royal_Spiral_Stairs_Comp_1484159215.blueprint
Royal_Spiral_Wide_Stairs_1484162191.blueprint
Royal_Spiral_Wide_Stair2_1484162246.blueprint
Click:
