So, the five hour hat ended up being a 6 1/2 hour hat with a multi day delay while I resisted the sewing up.
One good thing about making a mistake with the first caston (I can't really think of two, honestly) was that I was able to see that my heavy worsted weight yarn was going to create a gargantuan hat!
On the flight back home I started again, but started with a gauge swatch (gasp!). From that I realized that my cast on needed to be 100 stitches for the brim (vice 120) but I kept the spiral the same, though I knew it would make it more dramatic.
By the time I landed, I had all but the final decreases completed. Then it became a game of picking up the hat, putting it down, finally blocking it, and then moving it around and carrying it with me for days without sewing it up.
I chose the colors with intention. I thought I'd use up the handspun from Partner's Christmas hat. The hat only needs 30 yards of the contrast color, so I checked before I left and I had about 37 yards - perfect! Then I decided to look for another light, natural color yarn and found this. The origin of this yarn is a separate post, but it's an orphan, no label and just my touch-intuition to tell me it is 100% feltable wool.
Pattern: Escargot (and ravelry)
Yarn: no idea! mystery yarn that was given to me and the last of the hand spun, 170 yards
Modifications: caston 100 stitches for the main hat, but kept the spiral the same
Knitting yardage total 2012: 566