I would think they did the first row over again until satisfied with the space.. That's what I would do anyways. I tried it with that blk n yellow batman. It works
I followed the pattern for the first 2 starts. Then I did the first pattern #1 and last one #18 until I thought it was good enough space. Be careful though, on the sides you have to take out strings. So make sure you know what one is which. 🙂