Funny you mention that. I have been playing with distribution on tamping techniques for the past month. When I changed machines from my Isomac to the Faema, my shots went to pot. Uneven extraction, side channeling, channel jets shooting me, it was just a nightmare mess.
After several different techniques, I found that a slight rotation of the PF fixed my problems. I still grind and dose the same, but my first leveling tamp I rotate the piston ever so slightly, 360 degrees. That slight orbital compression, light portafilter tap then tamp to pressure did the trick.
I went from this...
To this just by changing that one small variable
I am looking forward to the tamper road show so I can see how other tampers/bases/baskets affect the extraction.