I used a chain cast on that ended up VERY loose (method described online here: http://www.loomahat.com/chain-cast-on/ ). I would not recommend it for a finished edge. If I did this again, I would use the long tail cast on for a tighter edge.
Worked about a 1” brim in k2, p2 rib. Used u-wrap for the knit stitches, but it will be more even if you use true knit.
Continued around in stockinette stitch by u-wrap knitting every stitch until hat measures 8-9” (small adult) or 9-10” (large adult). I used 8”, because I have a petite head size.
Cut a long tail of yarn and use yarn needle to thread through each peg loop, removing them from the loom.
Pull tight, secure, and weave in ends. I used the tail to seam the last bit of the top head hole closed. Some people even hide it with a yarn pom pom.