Changing your Fiscal Year End in a live system with history

Summary

We need to change from a 9/30 FYE to a 6/30 FYE - pros /cons of prim vs sec leger

Content

We have been live since Nov 2016.  We recently combined with another organization and now have to change our fiscal year end from 9/30 to 6/30.  It has been recommended that we set up a secondary leger with the new fiscal year since that is easier than setting up a new primary leger.  We would be interested in hearing the pros and cons for each.  We would also love to hear from anyone who has done this - what you did and lessons learned.