It will be tough to see white ink in the maintenance tank because when it sucks the color and spits it in, it will just mix with it and make it dark.
after you do one of those cleanings you should wait a couple minutes before doing a nozzle check, the white ink can foam up in the print head and cause mis leading nozzle checks, if it does not still work than you might have to take off printhead and bleed your dampers, i had to do this once.IFs emergency and need to print before monday i will help with how to do that, or you can wait to call tigers, which their probably still working lol, also theirs video on youtube, just look up neoflex printhead removal.