The hardest part about the zipper was getting my sewing machine to sew through the layer of felted yarn. Had to work it alittle. I am sure the next one will be that much easier.
This bag is 12 inches high, so there is plenty of room for yarn projects to go. I think you would say it is like a duffle bag shape. I used Cascade 220 (2 strands plus a strand of variegated sock yarn)