Personally, I've always ended up doing things in order - take Homeworld, sort of Wounds, then go down the lifepath.

However, does anyone do things different? Or know the official ruling on this? I know doing it after the lifepath will generally get you some slightly tougher characters, depending on if you took any Toughness boosts...

Starting Wounds are selected when you pick your Homeworld. You're able to move from top-to-bottom or bottom-to-top on the Origin Path, so it's largely up to you.

I do totals from the lifepath. But then again I award extra wounds when the character's toughness bonus goes up too.

As a GM, I don't make restrictions to Origin Path choices as long as the players come up with a good story (I don't any reason to restrict this, save for making characters faster), which means we do it in the book's order (Homeworld, Birthright, etc). The only factor I take into consideration while calculating Starting Wounds is if the Homeworld applies modifierts to Toughness.