with regular developers you can nail film speed and developing times in the same day. I used to have one that the company I used to work for issued me. Damned handy. I have one for film built in to my Metrolux II but I have to find the instructions to use it. They are not much use with ABC or PMK . I don't have a blue channel which I think I remember you will need to read negs with stain.

lee\c