Scene by scene is allowed as long as no dialogue, narration nor stage direction is written.
One of the our Assistants, BrickZed, made an Outline for their canceled NovemBEAR Project in the middle of October if you would like to see what they did.
https://docs.google.com/document/d/1I7BJoBDEbBqWwHztqogLIPAtkinoMkWXCrq2EAFVXsQ/edit?usp=sharing
Keep in mind that the more you pre-plan the higher the possibility you’ll screw yourself over when comes to the Jam Theme Announced two weeks before the Jam starts in May.
As long as nothing you wrote before the beginning of the jam ends up in your final script verbatim, it’s fine.