"I know that I need to get a densitometer so I can properly EI rate my film ". I also thought I needed a densitometer until I read about a method described by Horenstein in his Beyond Basic Photography. Basically it involves sandwiching a Kodak No. 96 ND 0.10 filter and a developed but unexposed frame and comparing that density with frames exposed to Zone I at various EI's. Not very sophisticated but it sure seems to have worked for me.