Heyo.
Are you trying to run it off a command like size or job (change to adopted)?
Or physically change the files in the GRF? If you resize the sprites; this will also affect the child and job commands as a knock-on effect.
Alternatively, replacing the Doram Sprites with your desired frames and sprites then changing to those classes will also work.
ACT editor comes with a ScaleX, ScaleY On every sprite added into the act per animated frame. You can scale them down by using a value below 1. (like 0.5 to half their sizes respectively). This value then needs to be added to each and every frame in that animation, then all 8 directions for that action, then all actions - idle, attack, take damage, die, pickup and so on..
Hope that helps!
Grey