It is recommended that you take a little time in the beginning to see how your records will be handled. After you have created your merge rules, randomly view a few groups of duplicates to see if the merge preview is populated the way you want it. Then manually merge the group and check the final record in Salesforce.
Sometimes your configurations in Salesforce effect the way Cloudingo is allowed to merge records. Keep in mind that rules in Salesforce take precedence over the rules you create in Cloudingo, for example, ownership rules or field formatting.
We recommend that you use this method to check a sample of each object before running mass merge or automation.