I use the Walthers early 4427 CF kits as a standin for the Bethlehem 4526 CF covered hoppers as it is unlikely we will ever see that kit in mass produced plastic. I use the Exactrail cars for prototype 4427 earlies and the Protos and Tangents for the late model.
I have bought a lot of the Proto2000 PS2 4427cuft kits cheap on ebay. The project I am now doing includes the following:
Stripping the original paint
closing the support holes for the roofwalk on the end of the cars and on the roof itself
assembling the kits
applying the Plano Models brake piping and roof walk supports (34x 0.4mm holes per car)
eschange the roof hatches with 3D printed smooth ones
repainting in BCOL dark green
I have now finished the first batch of two cars, the next will be decalling, I alreday got the appropriate Microscale Decalsheet MC-5018, but I will have to do some additional custom decals for these cars and am trying to find appropriate photos to make the Adobe Illustrator files.
As these cars are pretty fragile, I am now experimenting with how to store them safely in the original boxes.