When I heard these had come out, I wanted to try them out. So I bought three coal wagons and one grain wagon.
Again they needed Kadee #148. Again they needed some work, but not like the log wagons did.
All only had to drill out the coupler retaining screw hole just a tiny bit bigger, I could not get that screw (supplied with the model along with a coupler box lid) in ! The drilling made it a snap to put the coupler in – I took an axle out of the bogie to do this, taking care of the detail on these wagons.
So within an hour they all were done, and await line tests on a layout. A lot better than the flat and log wagons.
And for the price, quite OK , factoring in buying couplers as well.