Default Calendar permissions

I have been searching for a solution to adjusting the Default setting from Free/Busy to Reviewer. I've seen this question asked but never answered properly. Here is what I want to happen:

Use either EMC or Powershell to change what the defaults are PRIOR to creating a mailbox in Exchange 2010.

Step 1: Create a mailbox

Step 2: Confirm Calendar permissions on newly created mailbox

Anonymous = none

Default = Reviewer

I do not want to have to run a script or anything POST the creation of the mailbox.