Last liter of Tetenal's developer (that's mixed from 3 parts, and likely has a different replenishment rate than Kodak SP Lorr) was sufficient for 26 30x40 cm prints, developed in a 40x50 cm Jobo drum. As a starter (again, don't know if SP Lorr requires starter) I simply used around 30ml of the last batch of dev saved from the previous session. Halfway through the liter, I dump two thirds of the dev and mix the rest with fresh dev. I use 200ml for each print and mostly use drum's entire capacity, meaning I fill up the 4511holder as much as possible (e.g., one 30x40 + one 18x40 with two square enlargements). Hope this helps.