no problem friend. a comment or review is more valuable to leave points. this model based on the work of the tumbler blueprints. You can find them here: [link] And here's a very good tutorial that illustrates better how to develop this model. here: [link] personally took me between modeling and render, almost six months. with patience and perseverance will achieve these results, it's just work.
its a HDRI Dome you can download it here: [link] is the one I use the HDRI Dome, in high resolution, is perfect because it does not require the backplates to achieve an excellent result. Hope this helps. regards