adobe illustrator - How to make spirals into endcaps for strokes?

I'm creating an illustration for a quote and I want to finish the strokes with swirls -like in the image below- but I'm having problems making them look similar. I'm using a spiral tool and adding a circle dot to the stroke but the results differs from one to another.

Do you know a method to make them and then to replicate so they mantain a visual unity or can you point out a tutorial for a similar process (perfect swirls at the end of a stroke path)?

Thanks in advance!