Part 1:
Which shader do you think is the best to use for a production? I want it to be as fast as possible and I have been told that Mantra Surface is slowing down the rendering because of the displacement part inside the shader.

It's outdoor scene, HDRI lighting, there many wooden objects (so textures for color, displacements and light reflections), there are also few object reflected and refracted small models.

Is something I can modify or delete to make an existing shader faster?

Part 2:
I did some rendering over the network and is going really fast but there is some delay in order to start, I think it is because of the textures size, (4K), do you thing is too much that size of textures?
Also is it gonna help if I will combine all the textures in one shader and assign the right texture to the right object using an attribute?

thanks in advance for any tip or advice!