Which one does better filtered coffee? DF64V or Timemore Sculptor 078S? #df64v #timemore

Today we are comparing 2 similar grinders for making of filtered coffee. The 2 grinders in comparison are 1) DF64V 2) Timrmore Sculptor 078S The DF64V comes with the follow specs : 1) 800 rpm to 1800rpm 2) 64mm DLC flat burrs 3) Position of the burrs are about 20 to 25 degress from the horizontal 4) use a bellow system to get the retention of coffee ground to near zero The Timemore Sculptor 078S comes with following specs: 1) 800 to 1500 rpm 2) 78mm espresso base burrs with timemores patent design 3) pair of vertical 78mm burrs 90 degrees to the horizontal 5) Use a knocker to reduce retention. I have set up 2 tests to check the existence of the bitter aftertaste that i keep getting from the 078S. First test 1) grinded 15g of coffee beans 2) use the bellow or knocker to reduce the retention as close to zero as possible 3) do a filter coffee on both using 1: 15 coffee beans to water ratio 4) brew with the same set up and at 92°