First time trying out the Mohair version of the Oslo hat, and I definitely struggled with gauge and had a couple of false starts on this one. I had to try out a few different needle sizes and had to adjust my number of cast on stitches a few times until I was able to get the fit right.
I actually really like the tighter gauge and the fuzziness of the mohair version, although it obviously took much longer to knit than the standard Oslo hat.
The super long brim seems a bit daunting when knitting up, but I think it’s my favorite part of this pattern, especially since it’s long enough to fully cover my ears. I’ve noticed commercial hats will start riding up on my head when I wear them, and I find I have to keep tugging them down throughout the day. That’s not been an issue with my Oslo hat, it’s basically made my other hats feel almost unwearable by comparison.
YARN & NEEDLES
I cast on with US3/3.25mm needles and then immediately sized down to US2.5/3mm to knit the body.
I normally knit the Adult Medium size, but I did not meet gauge so I needed to cast on 128 stitches.
I used Sandnes Garn Sunday held with Tynn silk mohair, leftovers from my Balloon Cardigan, and it’s kind of nice having a matching accessory. 
I didn’t make too many alterations or modifications to the pattern and followed all of the recommended measurements.
BRIM
For the brim, I cast on using Longtail CO method because I find it easy to pick up stitches from this CO. I then marked every 10 stitches using a safety pin type stitch marker, directly into the cast on stitch itself. This made it super easy to line up the stitches when folding the brim and knitting together.
DECREASES
I modified the decreases using a k2tog-left, instead of the Slip 1, K, pass over stitch the pattern called for. This looks to be the neatest left-leaning decrease stitch yet, definitely better than an SSK as well.
I followed this video for the k2tog-left:
https://www.youtube.com/watch?v=qNu5gS5fyAc