You could cut the slot off the bottom of a fig and shape it with files. Longest and hardest method but it is also the most durable. Alternately get some scrap figs (GW Orcs come to mind) and cut the horns off their helms and use them. Other designs can be found in Shogun, and The Last Samurai. Samurai helms were individual and reflected some of the personality of the wearer.