Looks like a nice and interesting kit. Is my impression correct that this is the first kit of the Staggerwing in this scale?
I have to build at least one as a Finnish bird some day.
Now I'm not an expert on the Staggerwing, but is that engine correct? 18 cylinders, 9 cylinders per row. Makes me think of an R-2800 Double Wasp. Looking at the
wikipedia article, it seems the engine closest to the kit parts would be the Cyclone (9 cylinders, single-row), but then you'd need to do some modifications.
Anyways, fortunately there are aftermarket engines (e.g. Twin Wasp Junior) available. Even the Jacobs L 4 that I doubt to be covered by any manufacturer,
seems to be of pretty traditional American radial engine design and shouldn't be hard to replicate with other engine parts.