As guitar sonatas go Ponce's are at the top of the heap for lots of good reasons (better mastery of form, a succession of memorable tunes) but Matiegka's Grand Sonatas are worthy of attention.
If you want to introduce a guitarist who might never lay eyes on the score of a piano sonata or string quartet by Haydn, Beethoven or Mozart Matiegka's Grand Sonata I is a great piece to go through. Sure, it might seem conventional and too plain but that makes it all the better for showing a student how sonata form can work in the guitar literature. There's no themes taken up in expositions that are abandoned in both the development and recapitulation the way Sor's Op. 22 does. There's no tricky reverse recapitulation pattern of the sort Sor did in Op. 25. Those merit study by guitarists, of course, but Matiegka's sonata is a better example for guitar students for how sonata form would be handled on the guitar in a way that would be indicative of how non-guitarists tended to handle the form. If that seems too esoteric a point to be appreciated, fair enough.
Anyway, the full score of Matiegka's Grand Sonata I, 1 (minus the optional ad libatum passage composed by Wenatchee The Hatchet) after the break.