I'm now more convinced that reducing the dose stops it but past some point it gets sucked up and sticks. 3 different beans and no sticking.

My reason for past problems might be down to 14g of monsooned malibar, dark roast. That hasn't stuck since day 1 but the volume happened by accident. They have a lower density than many and I expect to use up to 1g+ more using any other bean. They all vary a bit though. I suspect what is happening is the same as I used the BE on purpose especially the single. I'd up the dose dose slowly until it stuck and then add another 0.2g and all would be ok. Any more and the strength of taste tends to drop off and had more effect on grind setting. I know I was hitting the shower screen because I used the hole in the shower screen retaining screw as a guide to keep the grind timer set correctly - slight signs of a pip.

Things don't seem to be so simple on the DB. I used one bean at 17 initially and then upped by 0.5g but ran out before getting over 18.5. Those may be light beans New bean and started at 18 and no sticking but this one is a touch too strong so switched to the 14g. No sticking with 14 in it same as MM.

Puck behaviour when I changed the weight was as expected. 17 rather wet and a fair amount left when I knocked it out. Improved as I upped the weight. The 18.5 more or less came out cleanly. My 14g of MM does too and more or less falls out when the portafilter is inverted. I do know from early days with the BE that go too high and the portafilter has to be used like a sledge hammer to get it out. Even with a "sensible" dose it took more effort than the ones that have come out cleanly on the DB.