Guitar Octaves and Unison Notes Color Separated
A good way to see how octave and unison notes are organized on guitar is to use colors to separate the octave notes. The Chromatic Scale in the key root of E is a good balanced layout to see the octave separation.
On a right handed guitar, octave notes have a stair step effect from left to right and unison notes from right to left. When there is so many unison notes of the same pitch on the guitar. How does a guitar player know which ones to use?
The best choice in starting is to pick a fingering that covers at least two full octaves closest to the lowest root note of the chord being played. The highest notes in the solo usually journey back the starting octave. No rules can be set in stone, but the closest distance back to the chord is usually the best desired return point.
Completing a solo then falling back into the rhythm timing of a chord can be a difficult transition. The closer the mechanical distance back usually makes it an easier task. Practice with a clear mind map of the guitar fret board architecture results with better instincts to navigate around.
The above guitar scale diagram was created with Guitar Analyzer Publisher Edition Software