If you prefer a more symmetrical looking cloth, then knit 6 rows at the beginning and 6 rows at the end. I like the asymmetrical look so I used a smaller border (4 rows) at the top and bottom.

Gauge isn’t all that important in a washcloth. I usually have to use one size smaller needle than what the yarn calls for due to the looseness of my knitting. I’d start out with what Lily’s Sugar n Cream calls for (size 7) and adjust from there.