Personally I’ve always found high lift tints, mixed with 12% as usual, can give a good result over grey/white, but it depends on the white percentage and how evenly it’s distributed throughout the head. Let’s say for example that someone is naturally a level 7 but has the beginnings of white hair scattered through the front, say 25%, I often find the high lift alone will blend that away and give a nice blonde result. However, if someone has a larger percentage of white, say 50% and the white is very prominent in certain areas, then you may find a depositing tint is more suitable on that area, as suggested above.
In other words, salt and pepper grey will get a more successful result with high lift than a client with patches of stark white.