It is wise to practice first. Start by holding the sprue above a lit candle, say two to three inches. After pulling, be sure to keep the sprue away from the candle, otherwise the sprue will melt. Again, practice is important. There will come a time where you'll be able to pull the same thickness consistently.
Some individuals use real wire for rigging.
Depending on your scale, you want to choose a thickness that looks like it's about to scale. Sources for Scale Plans To help with the many questions regarding scale plans for a particular subject, the list below provides most known sources of scale plans. Try your inter-library loan. Currently, one manufacturer seems to stick out from others with questions generated on the list. For more information about Meikraft's ordering policy, please contact the list.