Zero thrust settings
I can't personally comment on the turboprop aspect, but with regard to piston multi's, zero thrust below 3000', feather above 3000'. And yes, I do know people who haven't been able to restart the feathered engine.
As mentioned above, zero thrust settings leave the prop in fine pitch with a manifold pressure normally between 11 and 13 inches. This configuration gives (in theory) realistic feathered engine drag with a rapid-response capability if you need to use the engine.
Maybe we have been doing it wrong.
camlobe