I can get power when i need it. If the shots within half a table i typically draw the cue ball a table length to maybe 1.5 table lengths and then i usually draw short for full length power draw. If i need extreme sidespin to carry the cue ball down table or kill it off a rail, i usually dont get enough spin and over/under run position.
However i'm not talking about powering through the ball to get lots of spin, but rather maximizing spin with lower speed shots. In fact, this came up because of some of your drills (as described by forcefollow
here). It's easy enough when the balls are very close together or when they're both close to the head rail but it's become difficult to consistently successfully do this when the balls are moved up or farther apart.
So (other than the two exercises described above) is there a way to improve on technique for off center shots? Either through more drills or physically (via stroke trainer or some other method)?