Well, I believe I've got it; and some decisions need to be made here for me.
1- Since I'll always be playing through my oppo 205
(which can decode the MKV Atmos files and down mix), I'll rip to that, but also use MMH to split the MKV files into seperate tracks.
but
2- For things that I want to also play on my computer for various reasons (i.e. to do some manual adjustments etc.) I'll also need to rip to the basic 7.1 and down mix to 5.1.
I have to be selective then; depending on how much I like the music and will play it often, and, to save space on the SSDs, which are an expensive storage.
At least we have numerous ways to "Skin the Cat" and rip/play & store this stuff off the primary physical disc. I just need to listen to some things and see if I can hear any difference in all this.