Thank you! no tutorials, it was all experimentation on my part. but what I was guided by is grouping the instruments together and isolating them on their own, then understanding where they are in the orchestra stage. a Basic idea is, your strings are always on your left, woodwinds always somewhere in the middle, cellos on right, brass is back end a bit, and percussion back end a bit as well.
So I grouped each instruments, i.E Violins, cellos/bass, woodwinds, brass, percussion, routed the output of each section to an individual altiverb plugin, used the same reverb type for all altiverb, but now I had control on each section's where about, parameters, etc. if you own Altiverb, you'll understand what i mean once you mess with it, it has lots of lovely features.
so that is the basic idea, but that always highly relies on the libraries you purchased and how they were recorded, some libraries like css (yes i have it) has that natural placement recording, but then i tampered with it a bit, so its a fight with how these sample libraries are recorded. I can tell you i've been back and fourth about it for a year and half now trying to fine tune it and i don't personally believe i nailed it, i think it'll take a-lot more fine tuning, the worst part about it is each individual piece of music I go through, specifically dynamics, demands I tamper with the parameters of each altiverb, sends, Eqs, so fourth exclusively for each piece, so it can be alot of work, but the outcome...is very worth your time.
I hope that gives you a general idea.