Composing for Solo Tuning

Hey all,

This semester I’m taking a composition elective. Our first project is to write a sonata movement for our major instrument. I want to write in solo tuning since I prefer the warmth of it. However, I think I’m a tad confused about how to write for solo tuning. I know the Bottesini is written in A minor for solo tuning and we transpose to B but for the score how does the composer reconcile this with the orchestra?

Can anyone explain in laymen’s terms how solo tuning works and how the accompaniment is composed?

Thanks,