Hello zwitter689, welcome to the community!
It is definitely an interesting project, and a great application for our Shake, nice idea! To give you an example, I have mine installed indoor, on a wooden window sill, and I am perfectly capable of getting the traffic (mostly the heavier one, from cars, buses and trucks) from the nearby road, which is around 20m (70ft) away from the Shake position.
So, as you can see, it has good performance even with a normal installation. Yours should yield more and better results. How was the quality of the data for your first experiment with the aluminum plate?
Another user in the community has built a small concrete vault, similar to your approach, and located it only 5 feet (1.5m) from the road. His managed to get people walking, jogging, and the usual automotive traffic. You can read his experience here: Small outdoor vault
Regarding your second point, as our Quick Start Guide shows, the steps to follow to activate the Shake for the first time are pretty straightforward: https://manual.raspberryshake.org/quickstart.html
Now the Shake will update itself once connected to the internet, and also push the data on our online freely accessible servers. However, before doing so (and here’s the techy part, but it is not overly complex) you will have to burn the more recent software version on the Shake SD card.
You can find it here, with complete instructions: https://manual.raspberryshake.org/burnSD.html#how-to-burn-the-raspishake-image-to-your-microsd-card-software-os-installation