This is an absolutely amazing and lovely build, no question about it. And I love Cragars and your build will look awesome on them too, so don't take this as any criticism or like if I was telling you about how to do as a builder.
But, given that this has a Beetle body, with its origins in the 1930s, with a Cord nose (about as close as you got to "the car of the future - today" in the 30s, and I guess that I don't have to mention why), and is powered by aircraft technology from the pre-jet era, and you also mention that you're aiming for wastelandish looks, I can't stop thinking that this has very much of a dieselpunk vibe.
Considering that, I would have thought about something older if this was my build, maybe some tall and skinny wires or something like that, just to complete the looks. It's not like you need the traction of wide wheels and slicks when you don't have driven wheels anyway. Narrow wheels will also have a positive impact on air- and rolling resistance.
But if you like the Cragars, go for the Cragars, I am not bashing them either and it is your build and you are the one that should be satisfied. It will look ace either way!