I spoke to a guy in the custom shop a couple of months ago. The guys that work there, have been there a long time. The fellow I spoke to had 20 plus years on the line before getting into the shop.
I think the more bells and whistles that are involved, the more tuning goes into the rifles. You can get custom wood for the rifle, they use an outfit called Calico Hardwoods.
I asked the accuracy question myself, I was told 1 MOA max. I then asked if the test target could be sent along with the rifle, fellow said that shouldn't be a problem, to just request it on the final order form.
Being the thrifty sort, I haven't resigned myself to come off the money to build anything yet.
peterc, I don't think it would be unreasonable for the seller to let you test fire the rifle, after all you stated they wanted "Top Dollar" for it.