I just compared several platinum prints made on Arches Platine and Fabriano Artistico White, developed in potassium oxalate and ammonium citrate, to a sample pack from Lodima Archival Materials.
I am not sure how "Natural White" from Light Impressions compares, but I find the one from Bainbridge to be a little too green for my tastes. Natural White is actually classified as a yellow-green on the Nielsen and Bainbridge website, whereas White and Pearl White are considered neutral whites.
For platinum prints I would recommend using "Pearl White." It is just off-white enough to not clash with the soft, warm whites in the prints and it isn't as dark or yellow as something like Antique White, Cream and Ivory.