Best order (hacks + styles) parent ?

[Mathiau]

I know that if you install various styles, that when you add mods, you need to edit each template individually...

now, if i install mods, and then import a new style, and choose the default style as the parent style.. (that has the mods) will the mods be carried over into the new uploaded style bad all changed i make to the default template, adding mods, should copy over to the new templateS?

Or do i need to mod each and every style individually i use, which method is better?