How to Set Gravity for large sprites ?

Hi guys, after working on a prototype, I'm starting working with a 2D artist. After few research, we found out that the size of our sprites should be 1024x1024p ( power of 2, and pretty large, as we're working on a 2D platformer but NO pixel art). Just to be consistent, we consider working in a 1pixel/unit space in Unity. Are we correct so far ?

If yes, the problem that we have is that the gravity/mass/drag and every force are really huge and this is pretty difficult to handle (even setting the different speeds is pretty hard). Do you have any advice ? Should we consider change the pixel/unit ratio ?