Changing Type (size) of Label

[prhood]

When designing a report to print labels, the layout is
based on the size of the label, e.g. 2"x4" vs 1"x3.5".
Rather than designing a separate report for each label
size, is there some way to reconfigure the report layout
to accommodate a change in the label being used? The
parameters pertaining to specific labelsa are all
included/stored somewhere in the system. Can one access
them?