Classes

I currently have QB Premier and am migrating to QBO.  I want to restructure my Chart of Accounts and discontinue using some accounts in QBO.  For example, the previous accountant set up 5 separate groups of accounts (5 salary accounts, 5 office supplies accounts, 5 rent accounts, extra).  I want to have 1 set of accounts with 5 classes.  I would like to assign the GL accounts I currently have to a class, hoping that when I run class reports in QBO, I will have the historical information in the correct class.  I have learned that I can not assign a full GL account to a class in QBO (can only assign individual transactions), I need to do this in desktop before I migrate.  I have also learned that I need the Enterprise version of desktop to do this.  It has been suggested that I download the trial version of Enterprise, make my changes, then migrate from the trial version of Enterprise into QBO.  Does anyone have any experience with this?