You can always go back later and add more fields to the sync.
Custom fields you create are not included by default but can be selected.
You can remove fields from the sync BUT BE WARNED:
- If those fields are used in any reports/tables, those will be deleted
- If you use that field in a SQL Query table, then ANY reports/dashboards built on top of that table will be deleted
- Be VERY CAREFUL when removing fields from the sync