I used a sweater knit that I had. The only adjustments that I made to the pattern was to raise the neckline by about 2 1/2" and reduced the width of the cuff bands. Everything else was the same.
The back is longer than the front, so this is a great top to wear with leggings and the sweater knit just makes it really cozy.
So now that I've had success with this, I'll have to challenge myself and try something with more than just a few pieces!