Hello YankeeInLondon.... perhaps I'm a bit late to chime in, but I can finally report great success using Portable Library to use MC across OS's!! Although I think my setup may be a lot less sophisticated than yours. I basically have 3 independent computers - to Windows PC's & one MacBook Pro. I can't address the RAID & NAS issues, but I can talk with you about the Portable Library function which is very easy to used and works great!! No speed issues on my Mac.
Here's my setup: My music is stored on my main PC, although it doesn't really have to be in this model. I then copied all of my music & my latest Library Backup to an external HD which I can now connect to either of my other computers and run MC and my Library (and playlists) look identical on all machines!! On my source PC, my music is stored on C:\Users\susie\Music\My Music. On my External HD "E", it is stored on E:\Music\My Music or /Volumes/E/Music/My Music, depending on which OS you're viewing it on. Also, most importantly, I have a separate installation of MC26 (latest version) on all 3 machines.
While MC does support a portable installation for Windows, I don't think it's portable to Mac at this point. But with the Portable Library its now a snap of the fingers and my music & all of my playlists magically work on that computer.
Now, it's all so simple. Here are my steps (after the first time, it will only be a couple of steps):1) Make sure you have the latest version of MC install on all of your machines that will be used to run MC.
2) Copy your music & latest Backup Library to an external HD (ExFat formatted).
3) Plug in the external HD into whatever computer.
4) Turn off Automatic Import: Tools > Options > Library & Folders > uncheck Run Run auto-import in background
5) Restore the backup library from external HD: File > Library > Restore Library > locate Backup Library on your external HD, be sure to uncheck "Restore Settings", which will preserve your customized settings as they are.
6) Verify Auto-Import is still off.
7) Added Portable Library Rule: File > Library > Portable Library > Add Rule >
On Mac: Rule 1 = C:\Users\susie|/Volumes/E
On PC: Rule 1 = C:\Users\susie|E:
It make take you a few trys to get everything working, but it's so easy once you get it. I had to struggle a bit initially, but if a file didn't play, I ran Locate to see where it's looking for the file and where it actually is. I did this by R-Clicking the audio file, selecting Tools > Locate > On Disk(external). That will tell you where it's actually looking for the file based on your rule, and it will help you determine if your rule is entered correctly.
Here's are my most recent posts where I received a lot of help to get the kinks worked out:
Mac Forum:
https://yabb.jriver.com/interact/index.php/topic,126123.0.htmlWindows Forum:
https://yabb.jriver.com/interact/index.php/topic,126128.0.htmlI'm happy to help more however I can.
I have struggled with this for several years (the manual way) and finally MC has made super easy!!