At the SAR conferences the United States Coast Guard statistics show 90% of all rescues are within 12 miles of shore. In North America SAR crews recovering large numbers are more likely to respond to the aftermath of floods, hurricanes, earthquakes or a terrorist event.
The interesting significant factor with the large baskets is regardless of influences they do not spin. When floating the folding end gates allow people to swim in. These aspects help the SAR crews not hinder them. Operationally the SAR Squadron may not want to fly an empty at 120 knots but the US military determined the envelope safe for all Department of Defense helicopters. 100kts at GW and 120kts EW is a reasonable and useful flight envelope especially considering human carriage is most probably hovering people out of harms way.
There are numerous video clips showing various litters on hoists spinning out of control. This is stressful for all parties but not a reason not to use hoists. The US Air Force Air National Guard determined in their Katrina after action report that when hoisting from large isolated groups families were separated. The assessment went on to say that had they used baskets the operation would have been more productive with less probability of separating those families.
Baskets can be deployed with equipment for longer distances. A jet ski, appropriate inflatable rafts, gear to ward off hypothermia and other considerations could be part of a SAR operational kit.
Given the US 90% scenarios two trained SAR crews the one with a basket is going be more productive during the “Golden Hour” or immediately after the event.
I believe you have to look at a particular region’s most likely large scale recovery event and use the best multiplier.