I made the entire thing using my size 5.5 100mm circular needles, and this worked fine for me. I also used an acrylic yarn instead of wool because I didn't want to spend too much.
I already had two balls of grey yarn, so went to the store to buy more for this project, but didn't realise until a few rows into my third ball that there was a slight colour difference in the yarn I had bought (oops!) but I think it looks quite cool and deliberate (I hope).
The most tedious part of the project was the tassles, as you have to cut hundreds of lengths of yarn to 40cm, then thread 4 at a time in each stitch, and I managed to do this over a few evenings. The entire project took me about 4 weeks, although I could have done it in 2-3 weeks if I had needed to.