Step on the (Classical) Gas
Matt Palmer breaks down his turbocharged hybrid plucking technique in this excerpt from his book The Virtuoso Guitarist, Vol. 1.

Classical plucking-hand fingering
p - “Pulgar” or thumb
i - “Indice” or index finger
m - “Medio” or middle finger
a - “Anular” or ring finger

The fundamental approach to this scale technique is quite simple. Pitches from a particular scale are arranged in three-note-per-string patterns, and the right hand repeats the fingering a–m–i. The sequence of attacks in the right hand is of the utmost importance. The sequence a–m–i follows the principles of sympathetic motion, much like the natural closing of the hand. It is therefore a naturally efficient way of moving the hand—similar to tremolo technique. The mastery of this technique can easily provide guitarists with a simple and effective method of playing scales on the guitar. Efficiency and ease of execution are key factors in the fluid and effortless technique required to play scales at great speed. Fig. 1 demonstrates the basic approach to a–m–i scale technique over an ascending C major scale.

Observe in Fig. 2 how each string begins with an attack of the a finger. Furthermore, the attack of the a finger consistently coincides with the use of the left-hand first finger, while the attack of the i finger is with the fourth finger. In the descending scale, a similar consistency can be found. The attack of the a finger now coincides with the use of the left-hand fourth finger, while the i finger is with the first finger.

As can be seen upon further study of this method, when playing scales that proceed stepwise I am always in pursuit of fingerings that allow me to maintain the consistencies found in figures 1 and 2. No matter the events that occur within the course of a scale—direction changes, shifts, strings with more or less than three notes on them, etc.—I always attempt to maintain or immediately return to the idea of three-note-per-string scales attacked with a–m–i. This adds a great deal of consistency to the method, and makes the process of fingering and executing these events much easier. Furthermore, as you will see in the advanced application of the technique, the vast amount of fingering possibilities that usually exists is replaced with a relatively small number of formulas that can be applied to various scenarios.