The minimum permissions required by the installation user are:
System Permission:
API Enabled
Object/Field permission:
Account/Lead
Read
Edit - on all HG Insights fields from the managed package
In some cases we may also require Modify All - this has been seen in certain customer integrations.
HG Technographic/ HG Firmographic / HG IT Spend / Account Scoring fields
CRUD, View All, Modify All Permission - on objects
Edit - on all associated fields