Directing the Split when Riving Chestnut Laths

How to stop the split from running off when splitting logs into laths in a riving brake. These chestnut laths are destined for trellis-work on the front of a traditional Basque chicken house. Splitting laths is preferable to sawing them for various reasons - it's cheaper, it involves less energy (rip sawing by hand or by machine), they're stronger (because the split follows the grain) and they shed water better (because the wood fibres are not cut) so therefore should last longer. They also end up looking pretty good.