Good luck, David. I think it's a cool idea and wish you success. I think sound in Z would be a big win for the scale.
David, Don't get discouraged and ... there is no need to justify yourself, show your products and great ideas and if somebody is really interested and really wants it he will buy it at your price, price is secondary. You will not get rich, nobody in Z will get rich. Niche market it is and will be for a long time.
David, sell it at the price you feel its worth, and let the market decide if its worth it. Just look at Gerd's locos. Its not cheap, but he has a small group of fans that are willing to pay his price, because quality it's never cheap.
