Hi Fastel,
Thanks for sharing your music, I enjoyed listening to the composition.
I use the Special Edition as my main library as well, I don't have MirX but I am familiar with the impulse response you are using because I have it in Vienna Suite.
There's no right or wrong as far as I am aware, there's only the sound you have pictured in your head for the piece you wrote and systems to take you there....
References are our best friends, especially when mixing, they tell us what's too dry, what's too wet, bright or dark, narrow or wide, they give us a lot of useful information and they help us understanding our listening environment too.
If I were you I would try comparing your mix to the references you like the sound of, match volume first, is it dry? Is it muddy? is it too wide or narrow? You can use the reference tracks to guide your decisions.
Originally Posted by: Fastel 
Also I'm not sure if it is overall ricght to panorama the tracks in the daw when I switch on the MirX Reverb of the player. Wouldnt I panorama the reverbed signal too?
I believe that if you are using the built in pan on your DAWs channel, which affects the sound after MirX since that's built into the instrument, in that case yes: you would be panning the whole signal which might sound different than what you want..... also the standard panner that comes with most DAWs alters the stereo information of every stereo signal that runs through it, I only use it for mono signals.... if you want to pan a stereo signal without losing information I'd recommend something like the Vienna Suite Power Pan or any equivalent that might be avaliable in your DAW. Hope that makes sense.
Overall I wouldn't worry about average/standard settings when it comes to reverb or anything else, they might work as a starting point but nothing more.
I always use the same roadmap for mixing, I balance my levels, then pan the instruments, then eq, then compress, then add reverbs and anything else including micro-automation if necessary. If only dry signals are provided (eg Special Edition) I balance all the dry signals before moving on to the next step, if room microphones are provided, I use them too from the beginning of the session and that means that I will need less reverb when I get to the reverb stage.
I do use a reverb in my template whilst composing but I get rid of that when I move to the mixing session.
This is in my personal experience the easiest and fastest way to obtain the sound that's in my head, however a different process might work for you but I insist on the importance of reference material because that's something that I learned after years of fiddling and it changed my perspective completely.....it just helps you making quick and bold informed decisions about your audio.
Hope this helps.
Sincerely
Francesco