Honestly... every piece is time consuming. The more detail they have the more time they take. Personally I like doing the harder pieces because the end result is worth it. Accuracy is something I can't get away from, so I put the time in to make it right. Once you get a system down it becomes less of a chore. I spent a lot of time sizing my Halo 4 helmet and it turned out to be 42 pages. Haven't printed them out or started it yet, but that one has countless little ins and outs. In the end it will be worth it, and that's all that matters.