Errr well, I think yes.
I have 3 GPo: 1 = small, 2 = medium, 3 = large.
By default 1 is applied, then, for graphics and so on, 2 or 3 is applied, and finally 3 is for directions (you know... holiday's photos).
I think it will be too much "fine grained" applying different quota to EACH user. Do you really need this? Why not create 3 level associated to 3 groups... it could be easier for you too!