Another option for the newspaper is parchment paper you get from the dollar store (parchment, not waxed in the cooking supplies section with tinfoil). It's clean, transparent, sturdy enough to use as a pattern, yet you can sew through it for quilting designs and it tears well. But I really love the 12" width and the long rolls. That 12" size and the traceability are key.
A size I find really handy for arcs is a CD, ah for the days of free AOL disks. I also have some other things, like a fiskars circle cutter, I've certainly used plates, and I have a compass but I'm not too happy with it. I've been watching the thrift stores and wanting to find a high quality drafter's compass that has the dial that you tighten to hold the position. I have seen them before but not now that I want one. My cheapo crummy Jr High style one isn't doing the job.