Didn't Brian say ages ago they were working on it?
I like the live stuff coming obviously and Live at the Rainbow sounds beautiful. BUTTT, hows about we finally get some new Queen music we haven't maybe heard, all cleaned up and remastered, eh Brian??
The unreleased studio stuff is still in the Queen "archive"... It isn't unreleased after you release it. ;)
If I were you, I'd do something else and come back once Brian and Roger have croaked.
Have a feeling that Silver Salmon might have been properly recorded. I mean that was the case with Feelings Feelings in the first place, we had a crap recording for years (which by the way sounded much like the Silver Salmon one) and then they released one with great quality (though I consider the compression, particularly on the drums, being a tad on the heavy side).