Referring to the charts linked to above are great for forward voltage and flux information, but the color information can be a bit misleading, especially with Lux IIIs.
Of all of the bins out there, I've used LOTS of the WO, WA, XO, and X1 color bins and all (with a few exceptions) have been white to varying degrees.
If you are looking for the whitest of the white, then the WO color bin is what you're looking for, but you have to take the color binning with a grain of salt. I've seen many TX1Js that looked whiter to me than TWOJs do.