Hi can you please tell me if I am better off using the white tattoo ink before I use the black so it comes out white and not a grayish colour thanks

Seems reasonable, though I had heard that white is a very difficult color to keep. May depend on skin tones though. The yellow on one of my tattoo's has faded quite a bit and needs a touch up, so I can only imagine that white would result in the same.
Best bet is to have a seasoned tattoo artist let you know--they've tried it all!