Purely because this is a pitching & chipping thread Mark i've messaged you the practice info personally. I suggest learning the full spectrum of shots relating to your 64° wedge,by this i mean , Full shot, punch , pitch , chip. In practice from 100% down to about 60 % for the four modes should offer you cover for your distances.
( exception being full shot : ie from 30/40 sand ..40% = 12 yds. (64 °wedge)
You can choose to calculate from sand or rough 30/40 ~ 40/50 inclusive or as i did learn the scale separately then add following as extra: (20% from 30/40 sand) appx.
nb. From my own experience sand 10/ 20% plays different course to course,best to take notes.
EXAMPLE: PITCH SHOT 30/40 ROUGH>