Way to simply reduce file size by 50% while keeping all media specs the same?

When using other compressing applications, it's always been super simple for me to just set it to reduce the file size by whatever percentage I want while retaining the same media properties as the original file. Maybe I'm blind or something, but Compressor doesn't seem as a cut and dry as that, and I don't know where to start. How can I go about doing this? I'm working with an MP4

I'm actually trying to figure out the exact same thing right now. I'll be sure to report back here if I figure it out

Would you be more specific about other applications, i.e., the setting you change to get the reduced file size?

Or, do you mean that you choose a percentage of the original frame size?

The current version of Compressor has a bunch of settings called "Proxy". In that group, there are "half size", "quarter size", and "eighth size" presets for ProRes Proxy, H.264, and HEVC. These settings refer to the frame size...