Best Workflow for Creating a Split-Screen 4:3 Video

I’m working on a video project for uni and I’d like some advice on the most efficient workflow to achieve a look similar to the image I attached. The aspect ratio is 4:3, and two videos play side by side with one on the left and one on the right. I also want to use many different clips on each side throughout the project rather than just two fixed videos. I’m unsure whether it’s better to start by creating a 4:3 sequence and then position and scale every clip, or to format all the clips first before placing them into the sequence. Any tips, tools, presets, or general best practices that could help streamline this process would be greatly appreciated.