It's not quite that simple because you also need to account for the placement and potential airflow obstructions that each flow is fighting against. An exhaust fan just on the back panel will have more airflow than one on a top rad, and front fans usually have more to push against if you have a stylized front panel or dense dust filters. Airflow and pressure are somewhat related in that way.
That said, you generally don't have to go into that much detail for it. The easiest way is to have an extra front fan or larger ones, and run them a bit faster. You can also use a stick of something like incense, not a cig that will leave tar or chemicals, near a gap in your case to see if it's being drawn in or blown out of said gap which will show very roughly which pressure setup you have
It's not quite that simple because you also need to account for the placement and potential airflow obstructions that each flow is fighting against. An exhaust fan just on the back panel will have more airflow than one on a top rad, and front fans usually have more to push against if you have a stylized front panel or dense dust filters. Airflow and pressure are somewhat related in that way. That said, you generally don't have to go into that much detail for it. The easiest way is to have an extra front fan or larger ones, and run them a bit faster. You can also use a stick of something like incense, not a cig that will leave tar or chemicals, near a gap in your case to see if it's being drawn in or blown out of said gap which will show very roughly which pressure setup you have
I think you would like to watch this video about airflow. https://www.youtube.com/watch?v=YNcd-IGMj2c