DJ,
I took lessons from Paul Gilbert in '86 - '87 and he was obsessed with sweep picking and probably about the best on earth at it too. His approach was simple, to try and get every note to sound exactly the same as the note before no matter what finger you use, what stroke (up or down), what string or if you hammer or pull. One sound, tone and feel. Think one. His advice for me when I started was to play a C chord form (5 strings, A string though high E string) starting with the pinky on the 5th fret of the A string (making the first chord actually a D.
DS = down stroke
UP = upstroke
pinky fifth fret A string DS
ring finger 4th fret D string DS
first finger 2nd fret G string DS
middle finger 3rd fret B string DS
first finger 2nd fret E string DS
pinky finger 5th fret E string US
first finger 2nd fret E string DS
middle finger 3rd fret B string US
first finger 2nd fret G string US
ring finger 4th fret D string US
pinky fifth fret A sting US
Play slow with a metronome. Make everything balanced and almost machine like. Play in half steps up and down the fret board 4 hours a day. Increase the metronome speed very slowly, when you feel compelled to speed it up wait, stay slow get the tone right and don't be afraid to dig in, to many guys play the sweeps to light IMO and the sweeps don't speak they just lay there like a stupid trick a kid can't wait to show off at GC. They have to be played with authority, that's what Paul was so good at. I took lessons at his apartment on Cherokee in '86 and he use to practice unplugged all the time and as the elevator door would open I could hear his right hand from the elevator, his front door was a good 20 feet away with the door closed. He knew how to dig in and play like a man!!!!!! None of that pussy sweep picking. You can do it. The key is slow and get it sounding like a machine. Dig in and get the note, don't just glide over it, make it count.