Great job BTW. If you want to raise the reflectiveness by a few percent you could do the following.
Go out and buy a paint brush a large bottle of Elmer's glue and some Mylar or an emergency blanket.
Paint the underside of the light with Elmer's glue then attach the Mylar or emergency blanket to the underside
and smooth out any bubbles and cut to fit. let it dry over night and the reflector should be more efficient then white paint.
But that's just me.