Using Nikor 2x3 sheet film tank insert
Yes, Curt, that is exactly the way it is to be used. The spacer is really necessary if you want to get all 12 sheets loaded. As I recall, it was used to start the first insertion, and placed on top of that sheet for each succeeding sheet.
I did not ever use all 12 sheets because I felt that was too much film for a 120 tank, so I used up to 8 sheets [the equivalent of a 120 roll, 8 shots @ 6x9]. Be careful of your capacity.
Also, note not all Nikor 120 tanks are the same. The earliest ones [with a Mass. address on the bottom] were shorter as I recall. A rubber insert was included to lengthen those tanks. And, some tanks leak. Check all that out BEFORE you load it the first time. Agitation is excellent with the tank and my negatives were always evenly processed using this insert. It is the best way to process 2x3 sheet film, IMO.