Good points guys. There are 2 reasons for this approach. The main reason is to get a little more variation in the daily espresso. eg, no Yemen one day, 10% another day and 30% another, and so on. The second reason it that I don't want to waste my Yemen on latte drinkers, so when I have visitors wanting lattes they get just my SO. I find that if I get the get the grind size for the Yemen in the LHS hopper just right for full Yemen extraction, I can leave it as is and control the back pressure using the SO RHS beans. I hope that all makes sense 🙂 Cheers, Paul