If you are a professional fiberglasser maybe, but I thought about doing it that way and for me at least it wasn't really worth the effort of fiberglass or body filler. The amount of times you have to mark, remove and sand it to get the right fit will takes hours of extra work that will give marginal benefit. After all that work you still have to paint it and you probably won't be able to find a paint match with the other vent bezels which will mean your cubby bezel is going to be a different colour than the rest of your dash, or if you just paint the interior part then the interior part will be a different colour anyway and you might as well have just done what I did. You're better off taking the extra few minutes to dremel the bezel properly and then use some type of precisely cut ABS plastic or other material to fill in the gaps and it will look perfect.
Check out the software in that video if you don't like the Timur approach, You get split screen functionality, a lot more customizability and I've been able to get the battery down to 0.2%/hour on deep sleep. That's almost 21 days of staying on without power. It also works with Cyanogen 13.0..