I contacted the guy building the theremin. He's never played one, or even seen one in person, so since i'm so close i offered to help anyway I can. He's going to contact me when it's finished. So hopefully I'll get a chance to try it.
Sounds like you have the potential for a real "Star Trek moment": observe but don't interfere... see what he does with the theremin without being "tainted" by previous experience :)