More ombré/balayage questions

[H0llyd86]

Ok so for all the ombré/balayage experts out there, just a couple of questions. Can you balayage with 3 colours? With the ombré you can but I'm looking to do a client tomorrow with very blonde hair, pre pigging, wash off and then all in one go apply the darker root shade, (7.31) mid length (8.3)and maybe just conditioner the ends as they're already light but love the balayage look with the lighter pieces framing the face......any ideas of how I can achieve that whilst applying the root colour at the same time???thankyou xx