Need help with UV unwrapping

I made a model in Blender, and have been trying to apply the following texture onto it. I’ve tried all the automatic UV unwrapping methods in Blender, but all of them results in some sort of stretching depending upon the angle of view in 3d view. I’ve tried adding seams and unwrap it, but since my texture is a stone wall texture which follows a pattern, that hasn’t been of help either. I’ve added the blend file and the diffuse texture below. Is there any other way to do it besides doing it manually?

LP_SM_LowerWal_Railing.blend (830 KB)

Tried it. Apply the scale of the model and it works well.

But how do you ensure that the textures flow smoothly from the front faces to the side faces? Until now, I’ve only used manual unwrapping and in that case it wasn’t an issue. But it takes a lot of time since I have to align all the textures with respect to their adjacent models in my game.