How To Modify AE Default Preferences Programmatically?

Hello!

Completely new to After Effects, I am trying to figure out how to (ideally!) set the After Effects default preferences so that on scene open/load the default color manager is set to OCIO and Interpret Footage has the color space set to ACEScg. I've been looking online trying to find any snippets of code to try and accomplish this, and I wrote this code based on what I saw, hoping this was correct:

app.preferences.savePrefAsLong("Default IME", 0, 0);
app.preferences.savePrefAsLong("Pref_Col_Managed", 1, 0);
app.preferences.savePrefAsLong("Pref_Col_Managed_OCIO", 1, 0);
app.preferences.savePrefAsLong("Pref_Col_Managed_OCIO_ConfigName", "ACEScg", 0);

However, when I try to run this script, there is no change to the preferences in After Effects, and no errors to help me figure out what else to do. 

Is there a way to accomplish what I want using code like this? Or is this not easily done and I should do something else to get this working? (And if so, what?)