The way SMART Merge works (and I've added 8,000 people this way) is record by record. What is frustrating is that once you successfully confirm a match, it would be real nice if we were offered the option of merging the REST of the confirmed tree (or at least all ancesters - to include siblings) of the confirmed person - or at least to be able to control how many generations you want to import. This feature would have saved me over 40 hours over the past 4 weeks. You also really need to fix the Automerge - it is combining all new indivs (all brothers, and or all new sisters) into one indiv - it makes the feature useless unless you are just adding information to people already in the tree.
