One of the most important things in rendering is to be able to predict what you'll need for post-production. Meaning, what elements you'll want to have for post adjustments and, most importantly, what masks. Again, V-Ray provides a vast list of amazing elements for total control in post, including a MultiMatte element for us to create perfect RGB masks. This means you will have to configure several Multimattes since you can only get three masks out of each one of them (Red, Green and Blue). For those in a hurry and less concerned with mask quality, you can use the Render ID element, which will automatically generate a color for each rendered object, regardless of its Object/Material ID.
As for the image format and bit depth, I always render to OpenEXR format at 32 bits with all the channels included. I can't tell you how wonderful this workflow is. After you try it, you won't settle for anything else. It's so easy to just replace the loaded file (or image sequence) in Fusion or Nuke and see the compositing script working just fine and even adapting to different resolutions. What a wonderful world (Fig.20)

Fig. 20
I also rendered a simple black and white image with the tan mask to work on it in post (Fig.21).

Fig. 21
Post-Production:
The main compositing was done inside Fusion 6.1. With all the elements and mattes I had there wasn't much I couldn't do in post.
Essentially what you do is reconstruct the rendered image (also called a Beauty pass) with all the separated elements and then insert masked color correcting nodes in each element connection to the main string of the comp in order to change the color of an object, enhance the reflection etc. I did some background and tan testing (Fig.22).

Fig. 22
After presenting some friends with a few different versions I decided on the tan and on the background. It's really important to have other people/artists give feedback on your work. It really helps you to refresh and see new things (good and bad) in your work.
So it was time for the final touches in After Effects and Red Giant's Magic Bullet. Next you'll see the evolution from render, to post-Fusion and finally post-Magic Bullet (Fig.23 – 25).

Fig. 23

Fig. 24

Fig. 25
Conclusion
In terms of execution, this took me a single weekend, but to this I would have to add several weeks of mental conception and some sketching hours. As my first humour piece I am really happy with the result. It was a very fun and light project with some tripping overworked hours on a Sunday night.
As an artist I feel this type of work was more liberating than my usual attempts to create something that looks real, whether it exists in reality or not. I've definitely become a fan of cartoony work. You can give priority to creativity rather than technical virtue, although it's still important to remember that both should walk side-by-side, as close as possible.