I asked Andrew Dahm at Westerfield for his experiences and he suggested I ask the groups.
Background: I have numerous Westerfield 2400 and 7400 series hoppers as I model an anthracite road. Some of the kits I have are older, flat kits while a few, maybe a dozen, are the newer unibody style.
Question: Regardless of the need for adding channels to the sides and ends for safety appliances, has anyone assembled the sides and ends of a flat kit to match the unibody and then followed the instructions of the unibody kit to complete the car? Is it practical?