Notice the double-stops that occur during the chromatic run in the first two measures of Fig. 6. In measure four, the 1-2-3-5 motif shifts down a half-step from Ab major to G major (implying a G7) before resolving to the C major chord in the next measure. In measures seven and eight, the same motif moves up chromatically from G major to A major before resolving to the D7 chord in measure 9. In measures 15 and 16, a similar Dm7-based motif shifts down by a half-step before finally resolving to C major.
As we can see, the voicings Van Eps and Reuss liked to use are sparse. This is due in part to the tempo of the performances. Fuller sounding chords would clutter up the performance and be impossible to play. Another reason for using these smaller, efficient voicings is that the melodic lines of both guitarists perfectly outline the chord progressions.
If you were leery of triads at the start of this lesson, I hope you’ve had a slight change of heart after working through the examples. For maximum benefit, find a way to incorporate some of the information and ideas found in these solos into your own compositions and improvisations.