Apparently when you are going to be knitting in the round, it's best to do your gauge swatch in the round as well.
You can cheat, and just cast on for however many stitches you want for the swatch, and knit across. then do NOT turn the work, but just start knitting again, leaving a long loop across the back of the work.
You'll probably want to use the crics for this, (even though you are not knitting in the round yet) because you need to be able to knit from both ends. if you have DPNs in the same size, that would probably be easier to manipulate.