Funny, I just posted this on another thread
I owned a Fiorenzato F4, a great grinder otherwise, I could WDT for 10 minutes and not a damn thing changed its distribution into the portafilter and subsequent one-sided extraction. The only thing that helped my distribution was the Lyn Weber blind shaker. Grind into it, a couple shakes right side up, a couple shake upside down, distribute, a tap against my hand laterally on either side of the portafilter to settle the circle, tamp and perfect extraction.
I did the shaking right side up and upside down because of vaguely remembering some stuff about particle size distribution
. It worked well for me, especially when WDT did not for my one sided extraction