What's actually required to mix your own pyrocat-HD? I'm working in 4x5 now with the unicolor rollers and I'm very curious about pyro. At the moment I'm using diafine (the box says it's not recommended for roller use, but I find that it works quite well as the slightly increased grain from constant agitation is a boon when I'm enlarging), but would like to try a staining developer. After reading this posting about incorrect amounts in bags I'm hesitant about purchasing the kits to make my own w/o knowing the extra purchases I will need for verifying the accuracy of my concoctions before going in.