I riveted the doublers to the wheelpant brackets after drilling and countersinking them but abandoned the two forward holes because I couldn't get a squeezer on there to dimple nor squeeze the rivets because it's blocked by a nutplate.
This seems like a mistake in the Van's instructions which, presumably, will be -- or maybe have been -- updated to add the nutplates AFTER installing the doublers.
Anyway, it's a very ingenious design that didn't become obvious to me until assembly and it fits pretty well. I do want to do some cosmetic fiberglass to fill in some gaps between the forward and aft pieces.
Next step is the leg fairing.