[deckar01]

There is another solution: Get a machine with flow control and a pressure gauge on the group head. You can saturate the puck at low pressure to avoid dry pockets, then ramp the flow rate up until the group head pressure peaks. If the pressure starts to drop you can increase the flow to maintain the group head pressure.

As for the 6 bar course grind theory: You may maximize the extraction of soluble coffee mass, but the concentration will be lower. It does not take very much extra water to ruin the taste and texture of a latte.