I've tried several times, but so far the results have been disastrous. As have my attempts to actually use an atlatl. Those things seem a wee bit trickier than slings. I'll keep working on it -- the graphic, not the martial art. Perhaps in Season Nine. Wish me luck!
There's also the embarrassing fact that atlatl darts can be substantially smaller, lighter, and of different design than thrusting spears of the sort Sarah carries in many of her graphics. I rather glossed over that bit. Oops