Your answers provide a ton of insight.
The reason its scaled weird is probably because your original OBJs were made on alternative units. Like instead of 1 to 100, its 0 to 1 with lots of decimals. Like perhaps Maya and maybe something else was used.
This is the mesh I'm trying to import. It's perfect in Max but in Sledge, not so much.
https://www.dropbox.com/s/uu6fh2lzm5xrnzs/cave%20mesh%20final.objEDIT: The more I use Sledge, the more I like the sort of preview you get when you go to create new arches and torus.
Take or leave it, may I suggest that there can be a OBJ importer (with options dialog) that allows the user to preview the result, scale it, and do whatever before it commits to being turned into brushwork. This could be a tool with the brushwork stuff, or a feature under the file menu, doesn't matter. These options could also help distinguish between using Triangles and Quads. Once source stuff is implemented, I'd love to loosely rough out the terrain in 3D then port it over and convert it to displacements for smoothing and sculpting. As you know, displacements only work on brushes with 4 sides.
PB, I'm really passionate about Sledge's development (in case you didn't notice). Never more in my life I wish I could code so I could help this out. It's a good thing and I want to see you make it the new standard in Goldsource/Source/Source2 mapping.