Oh and the back flushing thing - that’s detergent not acid - you’re cleaning the coffee oils from the exhaust pipe work, not dissolving calcium. If you don’t have PulyCaff then a crushed up dishwasher tablet is exactly the same thing. Only use half a teaspoon at the most though.
I'd check that your machine is level. Sometimes it can cause uneven extraction. Also maybe a puck screen might do you a favour and help with consistency. I got one from Shades Of Coffee, was very cheap.
Getting closer. Flow is good but there’s this dead space on the left hand side of the basket
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