derek, i assume you are going to use the same amount of developer in the tank even though you want to develop a single roll. in my experience, the developing time remains same if i use stock solution(D-76). i decrease the developing time by 10% when i use D-76 1+1 for ilford pan 100. you should figure out this cut for yourself. however, my guess is, this should not matter much for a high speed film like Delta 400, although i have no experience with it.(posted 8908 days ago)putting an empty reel is a good idea to keep the agitation same. and hey, don't forget to post your results.