Gabaston is written for full orchestra, chorus and soloists (soprano, mezzo-soprano, 2 tenors, baritone, 2 basses). 

Composition of the orchestra
Libretto Act I
Libretto Act II

Act I full score
Act II (sc 1-7) full score
Act II (sc 8-10) full score

Scenes
Act I Prelude (Gabaston, Priest, chorus)
Act I scene 1 (Warwick, Mortimer, chorus)
Act I scene 2 (Isabella, Margaret)
Act I scene 3 (Gabaston)
Act I scene 4 (Edward, Gabaston)
Act I scene 5 (Edward, chorus)
Act I scene 6 (Warwick, Mortimer, chorus)
Act I scene 7 (Isabella, Margaret, Edward, Gabaston, Mortimer, Warwick)

Act II Prelude and scene 1 (Edward, Mortimer)
Act II scene 2 (Isabella, Edward, Mortimer)
Act II scene 3 (Isabella, Margaret)
Act II scene 4 (Isabella, Margaret, Gabaston, Edward)
Act II scene 5 (Margaret, Gabaston)
Act II scene 6 (Warwick, Mortimer, Isabella)
Act II Prelude scene 7 (orchestra)
Act II scene 7 (Edward, Warwick)
Act II scene 8 (Margaret, Gabaston)
Act II scene 9 (Edward, Gabaston)
Act II Prelude scene 10 (orchestra, chorus)
Act II scene 10 (Gabaston, Edward, a Priest, chorus)