Yesterday morning, I was able to complete my first set of 4 roofless woodchip boxcars. Numerous pictures postes by George Dutka on his blog were used. A big thanks to him for sharing this precise information with us.
I must admit my cars are far to be exact replicas. I had to work with many limitations such using old Roundhouse boxcars and decals that aren't perfectly fitting my use (well, none truly exist for this specific purpose). That said, I think the result catch enough the prototype details to look good near higher-end models.
I've learned from my mistake and decided to use Future acrylic finish as gloss coat before applying detail and later to seal them. It seriously improve the quality. No turning back from now. Next step is to try mixing Tamiya flat clear with Future. Looks like and can make a very nice dull coat.
Next step is to weather and make loads for them. However, that will wait a little bit since I'd like to complete building and decalling the five others that are still in progress.
I also decided to add decal to my 3D printed woodchip gondola. It won't be prototype, I couldn't find suitable "CN RAIL" decals, but it will be a working model. I didn't gave up about this particular prototype yet. Seems like there is some interest in producing this model, particularly from the Maritimes. Good to hear that!