Mason Dixon KAL

I recently finished one with 33 cast on stitches across and 10 bands length; finished product was approx. 8" square (a bit taller than it was wide--I don't have it near me to measure).
 

To go pretty much by the pattern it would be any number that is 45-6x, so 45 or 39 or 33 or 27... If I go smaller, I might do 35 and have 2 stitches past the edge-y slip stitch. I like two better than one.

The finished size depends on your gauge.
 

I made one on size 8's with 39 stitches. I stopped when I thought it was large enough. Funny thing though, I washed it, and now it is a rectangle :)
 

Here's mine:

http://flickr.com/photos/29278394@N00/147699342/in/set-546680/

The previous commenters gave great instructions. I added a row of single crochet around mine.
 

As another commenter wrote, finished warshrag size will vary with gauge. However, here is a comparison of my "normal" warshrag size and a smaller version....

Normal Warshrag (knit as the book calls for):
Cast on: 45 stitches
Ballband stripes: 11 (5.5 pattern repeats)
Finished Dimensions: 9.25" wide by 8" tall

Smaller Version:
Cast on: 33 stitches
Ballband stripes: 8 (4 pattern repeats)
Finished Dimensions: 6" wide by 7" tall

The two most popular warshrag sizes seem to be casting on 45 or 33 stitches, but you could do other sizes. The pattern is written for 9 stitches plus mulitples of 6 stitches (9 + 6x sts), so you could cast on more (51 sts, 57 sts, 63 sts) or less (39 sts, 33 sts, 27 sts) depending on the desired size on the warshrag. I find the normal warshrag is somewhat large for a kitchen washcloth but perfect for a facecloth, but the smaller version is great for washing dishes.

Stephanie
 

I also cast on 33 stitches but do 9 rows of bricks and wind up getting nearly a perfect square on size 6s.
 

Thanks for the feedback!
 

I took some advice from a post earlier in the month (or late July?) and have been making mine with 39 sts plus 4 for an I-cord edging. I do 5 repeats of the staggered bricks (rows 1-12), then end with a repeat of the first 8 rows.

Like Lesliej I learned that you need to make the warshcloths TALLER than you think you do because they will shrink more vertically than horizontally when washed. (I'm a new knitter so maybe this wasn't a surprise to anyone else.)

I love the ballbands! I made a ton of them and now feel confident to branch out into other projects!