Hi Nick. 600cc of developer is plenty for 10x8 prints. I heat it in a pyrex kitchen jug and slosh it onto the print and there’s plenty top spare. And it’s plenty for a printing session of maybe eight to twelve prints. The loss rate depends on paper size and absorbency, developing times, and developer temperatures (evaporation). After the session I filter the remaining developer and put it back in the stock bottle. Typically I mix fresh developer every two or three printing sessions I think. So long as you’re producing negatives targeted at Grades 2 and 3 then 100cc of dichromate lasts ages.