"On the economics, things worked."

I would argue that they didn't. 25$ per hour for custom design work seems very low, I understand maybe trying to get a customer base but at that rate you are just going to get repeat customers who want the same low cost labor. Where 3d printing is great is if you can create truly custom things, not knick knacks that can be copied and mass produced by someone else. Selling the plastic itself is a no go, you have to go mixed materials, mixed colorways, things that take time to assemble, and then charge out the wazoo for custom work because the people that really want the custom stuff, will find a way to pay for it.