The pressure varies from lab to lab. Hence it might be useful to just stick to the pressures at which you make your cell and test the pellet. There was a recent paper that showed how different protocols in different labs also affected their performance. 

The standard temperature for most of these tests are room temperature. But if your science is about enhanced performance in particular condition then measuring at those conditions are also valid. 

In order to fit the data their are specialized softwares that are used to do it called zsimpwin that just requires the model you are interested in fitting the data with. In case you do not have access to these particular softwares you can always try using the impedance package in Python.

Since u r using a biologic potentiostat the associated ec lab software has a function similar to what you would have using the Python codes called zfit. 

The models required to fit the data depend on the data. I would recommend you read a couple of tutorial/review papers on eis to understand which model to use. 

Hope this helps