I thoroughly regret that when my kids were little and my budget was tight that I still didn't buy a very special tool. It was a turning duplicator and lathe made by (I think) Anker Rasmussen. He was able to make some very delicate spindles using his duplicating jig.
In lieu of that, I found a way, when building my wife's dollhouse, to create some very delicate spindles for the front porch. I used florist wire and threaded tiny wooden beads onto the wire. Then I added glue to hold each bead exactly where I wanted it. Finally, a coat of paint, and it was ready for the next step.
I cut out the curved sections that hold the spindles using my jigsaw. I then drilled holes into this piece to insert the ends of the wire spindles. I also cut out a smaller curved section for the corners and drilled holes in those to hold the other end. Once it was glued up, we had a lovely set of one-of-a-kind spindles for the front porch!