A lot of the problems with reach are actually associable with bad position - the way you hold the guitar. Start with where the beast actually is. Classically, the guitar between the legs with the left leg raised six inches on a stool (pile of books), or the ladies' (jazz) position, left leg crossed over the right. The guitar should tilt back into the body at an angle of zero to 15 degrees. The nut should be level with the left shoulder. the left arm should be at a right angle with the neck (GET THAT ELBOW AWAY FROM YOUR BODY). The fingers should be parallel with the frets, the thumb slightly above the middle of the neck. Try it this way before you start the reaching exercises, and try to do the up and down the neck movements from the shoulder rather than from the elbow.