The shape of the sound box, hourglass, teardrop, rectangle, ellipse, and so on, doesn't affect the sound of the dulcimer very much, although there is no general agreement on any of these parameters. Unless a soundhole design removes a majority of the vibrating soundboard, its shape has little audible effect. The dulcimer is played on one's lap or on a table, with its tuners to one's left and strumming hollow on the right. All you really need are your hands, ears, and a good instrument. Beyond the basics, though, are many playing styles, techniques, and accessories.
Picks come in various shapes, sizes, hardnesses, and in varying degrees of flexibility.
When you take your new dulcimer home, don't ever hang it above a fireplace.