Changing Rolling Stock in a Template Options

[beechcaptain]

I have AM, so changing rolling stock in an activity is no problem.

Now, I want to try changing them in the template so I won't have to each time I generate a new activity with AG.

Here's the question..... How many and which files do I have to make the changes in?

For example, say I want to standardize the AI locos to a group of SLI ATSF or BN engines, which files do I need to make the changes in besides the .act files?

Thanks,

Glenn