1. A method of effecting assignment to bins of records representing items in a dimensionally-modeled fact collection, the method comprising: representing a plurality of parameters on different portions of a user interface simultaneously, the plurality of parameters including a count of records parameter and a fixed cut points parameter; providing a count of records portion of the user interface configured to receive user indication of a desired count of records for one or more of the bins, the desired count of records used in assigning a corresponding number of records to the one or more bin, wherein a user-specified desired count of records for a bin is made either by specification of a value that is an indication of a number of the records desired to be assigned to that bin relative to the total number of records, or an absolute number of the records to be assigned to that bin; providing a fixed cut points portion of the user interface configured to receive user indication of fixed data value dividing points between the different bins, the dividing points used in determining how to assign records to the different bins; wherein a user change to the count of records portion of the user interface produces a corresponding change to the fixed cut points portion of the user interface, and wherein a user change to the fixed cut points portion of the user interface produces a corresponding change to the count of records portion of the user interface; determining actual counts for assigning the records to the bins by constraining records having a same data value at a specified particular dimension to be within the same bin, such that the determined actual counts of records at the particular dimension within each bin are different from the user specified desired count of records for one or more of the bins; and providing a user-observable indication of the determined actual counts.