Watch the 1-2-4 & 1-3-4 online guitar lesson by Richard Hallebeek from Scale Creativity Guidebook
If you play three note per string scales, one thing you can do to open up your scales is to play what I call 1-2-4 and 1-3-4 scales. In a 1-2-4 scale, you play a regular 3 note per string scale, but skip the 3rd note and extend to the 4th note.
In a 1-3-4 scale, it’s the same thing, but you skip the 2nd note and substitute that note with the 3rd note of the scale, then move on to the 4th note. So it’s still a three note per string form, but with a much more interesting intervallic leap. For left hand fingering, you can play those scales with slides or with regular fingering, or with two hand tapping; I don't care how you play it. Just remember, If it sounds good, it is good!