Soukous guitar solo are mostly built on a handful of chords and on a single diatonic major scale, the same way the blues is based on a basic chord progression and pentatonic scale. Of course this is a simplification, useful as a starting point and crucial to move the first steps into this style, but obviously not accurate enough to describe a musical tradition that is vital, strong and still evolving. Consider it a work assumption.
The basic, most common progression is I-IV-V-IV. The roman numerals refer to the harmonization of the major scale, i.e. chords built on each note of a major scale using intervals of thirds. You can easily find better and more exhaustive explanations anywhere on the web, just type "harmonization major scale guitar" or "harmonisation gamme majeure diatonique guitare" into google and check out the results.
If we refer to the C major scale the most common chord progressions used for solos in this context are:
I-IV-V-IV = C-F-G-F
I-V-IV-V = C-G-F-G
and many variations around those.
Here I tried to classify the transcriptions by progression type so that it is easier to study and understand them.
If you have any feedback or request or if you notice anything wrong in the classification just write using the Contacts form and I will be happy to read your messages.