One simple option is the "Pitch Wizard" kubb tool that utilizes geometry and ease to map out the perfect pitch in minimal steps. This compact device stores itself on a compact, handy reel that tucks neatly into your kubb bag, ready to unwind for your next match, just like you do! Made from Kevlar, this design minimizes the stretch/tolerance found in most string/line devices. Currently available from Kettle Moraine Kubb (.com) for $18.99, with a video coming soon to show you just how simple and accurate this tool has become.
A tournament version is also available, made from vinyl-coated aircraft cable, for $58.99.
Of course, you can always walk-off the sides, set the kubbs, and start throwing wood!!