[Trombone-l] Nelybel tuba etudes- fictional situation

[Jackie Harris-Stone]

My husband's novel is now including a young tuba student.  He has her playing a Nelhybel tuba etude.  She's about 11, has played for 2-3 years, and has quite a lot of talent and practices a lot. She was taught by a Russian for a year or two, and then a British teacher took over.  This occured about 1987.  
 
I gave him some suggestions of what she would be playing- I thought Blazhevich, perhaps Bordogni-, but for some reason, he found the Nelhybel etudes on the internet, and thought it would be a better fit.
 
Does anyone know of these, and would they fit the above scenario?  If not, and you were writing the novel, what do you think might she be playing for etudes?
 
Trombone content- almost every trombone teacher teaches tuba students, and us bass trombonists play tuba etudes.