The other day in fencing class I was asking my teacher about what kind of solo practice would be beneficial between sessions, and we talked about using one's reflection in the mirror as one type of visual aid to practice lines, transitions, guards and parries.
I then asked about practicing targeting on a wall or dummy and he said something really interesting that matches perfectly with what I learned in Eskrima.
He said absolutely, but far more valuable than picking a target and trying to hit it, rather align your body with the weapon from different guard positions, thrust, and observe where the point hits. That way you are learning from the core to the periphery, and the hand eye coordination come from the feedback loop of body alignment manifesting in a hit, not an external target pulling the intent and hoping that the body will follow ....
Your whole body will learn by what it actually does, not just by what you want it to do, and achieving your aim by using what you actually do, turns out to be much more efficient in the long term than hoping for an outcome and trying to find a way to make it happen ... I guess it's like the Zen archer folks 'losing attachment' to outcome - focusing their training purely on the process, so when all is in tune, the arrow naturally hits the target.
On a physiological level, this focus away from the periphery makes sense too when seeking to improve accuracy.
I've been painting for a long time, and have done a little sign writing too. Not sure if anyone out there has done any, or ever seen anyone else do it in the old style, (Have a look here if you are interested: http://www.youtube.com/watch?v=6YCF-7bms8Q) but for freehanding accurate lines, sign writers usually use an arm rest to help align the brush before the brush is put to the surface, during it's use, and when it is pulled off the surface. Both sides of the body are in use, sometimes even weight shifting and turning the waist.
In house painting, you do the same thing when you make a freehand line with a brush, you either support the arm on your body or with your other arm and move the hand, or keep the whole arm in a fixed position and move the rest of the body (walking or dropping down) to create the line. Basically you are aiming with your whole body, your hand being an extension of it, and thus the brush also.
Works well for brushes, but also for tip only, and edged weapons, and has the added benefit of conserving balance and power, and enabling efficient recycle to the next move with no loss of either.
As a point of interest, Sonny said he would 'sight' with his knees, i.e. if his lower body was in the correct alignment relative to is opponent he knew he could hit them without even having to look.