I'm using a custom blend texture on Boundary with the snow texture (512x2) and the concrete texture (1024x2). It looks fine in Hammer, but in game it comes out as half the size (so 512x2). I've tried scaling both textures in the .vmt but never got it working. So I just use .5 scale in Hammer, rather than .25. Seems to work fine.
Ah, but the problem you see, is that it appears like this in hammer:
As you can see, the concrete is fine, but the gravel is very large compared to the expected output.