Since several people have asked, here is further information about how I requested documents from the Kaunas Regional State Archives. The email address I used to transmit my request was kaunas@.... The documents I requested were internal passport and related documents extracted in a litvaksig spreadsheet. I essentially sent them a shot of the spreadsheet entries, which included the data they needed to locate the documents, such as names, dates, places, and archive/fond/etc.identifiers.
Stephen Katz