I don't know if Crubat would read this, or if it would be taken seriously but still, I love discussions were breast size implications can seriously affect a person's actions and I think this poll fits for such kind of analysis.
Considering Sakura's anatomy a double bladed (alla Darth Maul) lightsaber is completely out of question. Sure it is cool and all but not practical.
Single could be a more realistic option, however from a defensive point of view it vould leave one of Sakura's flanks unprotected at any moment .
So I recommend Dual...like Aayla Secura in SW Battlefront 2, I think. As a side note I've seen fanart of top heavy females using dual double blades sadly no one of them was close to Sakura in terms of size or magnificence.