Currently Sprytile wouldn't be able to handle higher res textures well because of texture bleeding. The way to deal with it is known but has yet to be implemented.
Yeah but with blend stuff you need all kind of masks for edge scratches and dirt etc...the shader will get big and maybe not that good for performance.
You could try Camera mapping if it's not gonna be seen from all sides or by projecting from multiple blended Cameras and baking that to another projection.
IMO in the final renders you should blur the background. It is very hard to focus on your model at the moment, it seems to blend too well with the background.
This is awesome, you don't wanna push the metal material to be brighter on the belts, seems to blend in too much with the leather. But honestly really liking the direction of this :)
Switch the viewport from Shaded to Realistic. Shaded uses no depth sorting for alpha blended meshes, which is faster but transparencies can look incorrect.