Around the same time, my LYS got in some of its fall yarn shipment including some Sirdar Tweedie. Yum! I thought: "What a lovely yarn for my new hat. I know that it is a little bit heavier, but since I want a hat of substance, if I can get gauge I should be fine."
After much swatch I thought that I had achieved success! I started knitting... I knit the folded ridge. I measured. I thought: "I'm a little bit off but it probably the needle pulling it out making it measure bigger than it should be. Besides - it isn't that much bigger." I kept knitting. Before I put on the peak, I realized that much as I loved the pattern and the yarn, my hat was looking unmistakably like a knitted toilet seat cover. In a state of denial, I convinced myself that it would be better once I knit the peak... I wasn't completely wrong. I was much better! But it was still very wrong. Take a good look at it. It will never be seen on my head in this form. I looks like something a pimp would wear. It is going to be frogged and re-knit as a different and more suitable hat. (Yes - I am open to suggestions.)
Lessons learned here? Gauge swatches are mischievous liars and you really can't substitute whatever you want no matter how badly you want it to work.