Tune it by cutting it shorter to heighten the tone, or gouging under the middle to lower the tone. You can also raise the pitch slightly by thinning the ends, and lower the pitch by making a simple saw slice or gouge in the middle. After you're done tuning all the keys, you'll want to re-figure all the nodes and mount the keys at those points. If you gouged a lot under some keys, use the salt method to find the nodes, because gouging moves the nodes outward. As long as the keys are supported by something soft and are not bound in a way as to restrict their vibration, mounting possibilities are limited only to the scope of one's imagination.
Imagination is our best resource.