jomichael,
The important thing right now is to just fill the major crack so that it is flush. It don't have to be pretty, just buzz it flat leaving the crack filled.
The idea is to just fill the crack and let it shrink if it wants to. Then come prep time for paint the only thing left to do is skim coat the area and sand it out for the finally smooth finish.
Like the problem with mudding a hole in drywall. You put mud in the hole, next day you come back for another coat to fill over the shrinkage, only difference is the bondo doesn't want to shrink in one day.
Dan
