I have been practicing swirls (spirals) with pen on paper. I JUST attempted my first row of spirals on a table topper. I decided to just go for it with a simple swirl. I didn't make it complicated. Just a simple swirl (in and out) and straight into the next. Are they the same size? NO. Are they even? Not yet. BUT I did it and I am OK with my imperfection and as I got to the 4th turn, the swirls got more even and more the same size. It takes practice.
My suggestion: Test it on a reasonably busy print.