Mark,
Yes, you can do mass changes to the policies like changing the storage unit, policy type etc ..
Under the policies you find Summery of all all policies, select this .. on the right pane you find all the policies attributes, whatever policies you wish to change you can select all of them and click on the respective option to change .. for example select 10 policies attributes in the right side pane and click on change it opens a single window .. there you can change .. it applies to all the policies.
NOTE: If you change a single attribute of the selected policies it applies to all.
Raghava.