I'll tell you all a story.......I had a customer who was a mighty moose hunter. His requirements: Flintlock, short barrel so he could crawl on his belly through the brush. .62 rifled bore and sighted in for 200 yards with a 140 grain 3fff powder load....there were no options about this load. Evidently the closest you can get is 200 yards to a mighty moose in MI.
I finally negotiated him from a 24" barrel to a 38" barrel. Anyway, got the gun done and drove all the way out to the range to proceed to beat myself to death sighting this gun in . It was !@*%&@ near dead on at 75 yards right from the start I mainly had to work up a load. It took me 2 days before I found the accurate load. .600 ball, .018 pillow tick, wonder lube and 95 grains of 3fff. It wouldn't shoot with less powder or more, 95 was the sweet spot. It actually shot surprisingly well. So, I lost 2 days work sighting this gun in.
I packed up the gun, a target, patch material and a dozen ball with the proper load written on the target. I get a call from the outraged mighty moose hunter not long after. He claimed the gun was an inaccurate piece of junk with a slow lock (this was his first flint gun) and wouldn't shoot the 140 grain load he required.
He wanted his money back of course. I told him to send it to TOTW to sell it. It sold in 2 days. I told Mark Silver this story once and it turns out Mark had turned down the order before I ended up with it...smart guy that Mr. Silver.
So, what did I learn here?
Don't waist 2 days pay working up a load that the customer won't use anyway, and to turn down orders that aren't something I want to build. The longer I do this the more work I turn away.
So, I make sure the gun sparks and functions and then box it up and away it goes. I personally don't want anyone working up a load for MY personal guns because I probably won't use the load anyway, and, I want a new unfired gun if that's what I'm paying for.