This project should work with lots of different Nixie tubes. I've used 3 different Nixie tubes. Just look for ones that operate in the 150-200 volt range. All you need to do is adjust the Anode resistor for the brightness that you want. Try a few different values 15k, 20k, 10k, etc.I don't have a good source for the nixies. Although some places to look are in old Oscilloscopes and old Volt meters.
It was my first time too. I watched a lot of tutorials in order to figure things out, and it took me a few tries. What you're looking for is a button called Copper Area on the PCB Tools toolbar. Select your layer, click that button, and draw a box around your board. Hope that helps.
The reason that I used those values is that I found 2 or 3 other schematics on the internet that all used the 10K, 1M, 10K values. So I just went with those.