H color I think you are fine either way. With I color, is the band just metal or will it have diamonds on it? Also, what size is the center stone. If it is a larger I color, I think you are better off with platinum. If the band is encrusted with diamonds, you won't see as much of the metal so you could go either way. I think if the stone is of a certain size in an I color the bright, gleaming white of the white gold in a metal-only shank may cause the I color to look for tinted.
I was thinking either the same plain shank I have but in platinum or the pave shank. I hadn't really thought about whether the pave would be white gold or Platinum. Do you think platinum would be a better choice with pave considering the stone color?