i’ve had to do this before on my own projects because a client wanted something a different res, the solutio was to go through each individual comp and put in the proper comp settings. then of course doing the same for each layer that needs it as well.. it’s meticulous and i hate doing it – i know of no other way. you might even end up having to change particle sizes, velocities, camera positions, depth etc.. depending on the project
the shortcuts might help out (ctrl+k or command+k for comp settings… ctrl+shift+y or command+shift+y for layer settings)
Dead the Fed