Not a percentage, but overhead should be in proportion to your market, right? Obviously the lower the overhead the more profit, more profit, more growth, more overhead, what then? Better your market! Where is your best potential for income? I think that is the larger question than overhead... Having been in the architectural business for over 20 years I have seen glory and destitution. I then sought out work that is fulfilling but without much profit, so my overhead had to decrease to very little. I have been patient and spent many hours of research to find my market, one I feel has the most potential for profit and fulfillment.
Having one the largest and best equipped shops, one would hope to have the larger a more demanding jobs to support it. Larry, I think you are one of the most creative and hard working smiths I have met. Following your work I have had a hard time understanding why other work besides industrial smithing has not been more accessible? It seems any large metro should have many jobs in entertainment and restaurant business- props, interiors, signage, sculpture, fountains, cars, motorcycles, etc. Maybe the market in Seattle is flooded with artisans as well? I can defiantly see your shop as a premiere artisans studio where anything could be possible and profitable! I really am pulling for you as well as the rest of your friends here are, we all wish you success.
Michael