Not yet, but I already wrote the business plan. Now, just gotta find the capital and so forth.
Check this out...in Mozarts time there were NO tape recorders or Symphony Orchestras available to just "Jam". It was all about the score. The first time the score was played would be the first time he actually HEARD it. Wrap yr mind around THAT!
I'm the same way. I always write out my scores before I play them. I've been in that habit since I was young and just writing guitar music. I just carried that over to orchestral composing.

FWIW, in Mozart's Vienna, composers generally did have access to musicians so they could get advice and hear their ideas played before the concert premiere. Mozart himself knew a number of musicians from whom he got tips. (at least, that's what historians taught when I was a music student)