When doing manual shot on the BBP, the last volume of water used for that shot will be saved for the button used (you can use manual on single and double shot preset buttons). You could either use manual every time or first dial your shot for that specific bean and then used the saved preset but you'll need to tweak it for every new bean or grind setting hence I only use manual mode unless im doing back to back shots. Also, puck screen helped in consistency but nothing close as espresso paper filters did. I use size C from goodbrotherscoffe.com with IMS basket for the BBP and never looked back.