However with todays battery prices, it is (Or it would be) hardly worth accepting the half-output of the 1xAA pack over the 1x123 pack, just for the cost savings of using a AA over a 123.
When I had a LS1 it was carried about 45% 1x123 , 45% 2xAA , and the remaining 10% (More like 5%) 1xAA.