1 - will, if not exposed, of course, in the Global switches - Max depeth at Reflection / Refraction.
The entire rendering process based on the ray tracing ( Ray tracing ) "from" or "to the" chamber of which renders the scene. If a beam directly or through reflection, comes to the camera, that is to become visible on the rendering, it is necessary to calculate the path, even if it came from a "room behind the wall»😁
2 - The larger the number of lights in a scene, the more the light rays have to be traced. V-Ray works as with his, and with standard maksovskimi light sources, but it is preferable to their own, vireevskie sources.
3 - Faster than VRayMtl without reflections and refractions than one material is not rendered.
4 - Do you understand all right. If the number of memory allows you to render static reykasterom downloading the entire scene as a whole, the rendering will be much faster than in the case if required dosing memory and the use of dynamic reykastera , for example for the same the VRayProxy .
Of: We are glad that you like RenderStuff, come in yet😉