Well, i guess my only option is to work on the Spas-12 in Milkshape 3D then, even though i've been trying to avoid that because Milkshape 3D's viewports are hard to work with and Milkshape 3D tends to be a pain in general, but anyway, you can't select parts of the model in the 3D view like you can in Blender, so i have to find specific parts i want to fix up in the 2D views, which is never a fun or easy experience unless you're working with a low poly model where it's not just a mess of vertexes and lines
By the way, something weird about Milkshape 3D is that SMDs keep their smoothing, until you do anything, then it welds all the vertexes together, this is because the SMD is imported into a single smoothing group, a way around this is to disable auto smoothing, but that could also mess up the lighting for any mesh you rotate to a different angle, so a better but stranger work around is to assign the mesh to the highest smoothing group, which for some reason makes it so the model's current smoothing is not affected by anything you do, even though all of the other groups will
Milkshape 3D's never really made much sense to me ¯\_(ツ)_/¯