I would suggest developing the project on a "regular" Arduino to begin. This will make it easier to get your code working because you will be able to use serial monitor to help with debugging. It will also tell you how much ram and flash memory you are going to need, including the various libraries involved. Hopefully, once it is working on the larger Arduino, you will find need less than 8KB flash and 0.5KB ram and you can then migrate to the Attiny.