Re-Initialization question

I'm going to reinitialize my delta for 0CO_OM_CCA_9 in Q. Since there's a lot of data in R/3 I want to initialize delta selectively. But i'm confused about what values I should give in the selections. My selection fields in the package are Controlling Area, Fiscal Year/Period, Cost Center and Currency type. Realistically, what values I should put so the Init doesnt keep running for hours and hours. This is the frst time i'm doing this. thanks for your help in advance

Fran