I'd like to hear about others' experience using the Global Account Mapping functionality. We have a few use cases for stat reporting, however, it seems we need to engage with NetSuite PS for the historical aspect. Has anyone "defied" this recommendation and embarked on the HTP portion independent of NetSuite PS?

I do not believe you will be provisioned HTP tool without someone in your company having MultiBook certificate. So, it is either PS services or someone else with MB certificate

thanks @Karina - it's already available in our account

then SuiteAnswers # 36433 will take you through the global account mapping; HTP can be tricky, however. Make sure to run all your financials and activate all inactive accounts - particularly if you have been using NS for a while