In our review, we used a 110GB FCP project in 4K 8 bit shot with a Sony dSLR. This is the actual project we used to create our Samsung Galaxy FE video review, and I used it because it is more representative of real world use compared to short and simple "test" videos with just a few clips and simple timeline. Hundreds of edits, grading, B rolls and audio leveling. I used a Samsung T5 1TB SSD for all media storage for this 8 minute video project. Why? Cause those of us who make long form videos for a living never store projects on boot drives- there's simply not enough room. We have a host of external drives for production.
This was on the 8/512GB 13" Pro model. It never faltered. Memory pressure in the green the entire time, even when using an external 4K monitor. Would I still go with 16GB for pro video editing? Yes! But I have to admit 8GB worked (I did avoid running any other programs beyond Motion briefly).