After messing around with it for a while, I am still not satisfied with this engine.
It did work, but you have to set the input psi quite high. Because of this, it goes above 1.2 joules in my replica. If you are handy with it, you might be able to improve it and use it. The previous owner had nozzle problems. It was pressed too tightly against the hop-up, damaging the top of the nozzle. This does not otherwise affect its operation.
Testing and demonstrating that the principle works is possible. Shipping is possible, at the buyer's expense and risk.