I think I can clear up a couple of things about these two releases..
Speaking of the quad version only, the mixes of the tracks from BS&T 'II' on BS&T 'Greatest Hits' are the same. The weird thing is that rather than both versions having the long album versions, it's the quad mix of BS&T 'II' that contains the single edits (ie the short version of Spinning Wheel etc). Even weirder is that Columbia definitely did a quad mix of the long album versions (it's out there on one of the Mike Robin reels) but chose to shelve it in favour of a mix that used the shorter single versions in their place. As someone else mentioned, the tracks from 'Child Is Father To The Man' will be different from the ones on the AF SACD released a couple of years ago because those were 5.1 remixes done by Al Kooper and the ones on the greatest hits are vintage quad mixes done by Mike Fusaro along with the rest of the album. Interestingly, BS&T Greatest Hits is the only album that Fusaro got a quad remix credit for, but you have to assume he did the quad mix of 'II' as well given that the tracks from II on Greatest Hits are the same mixes.
Probably of less interest to us but I assume the stereo layer of the Greatest Hits SACD will contain the single edits of the songs from BS&T II, which will mean it's the first time they've been issued, as the stereo layers of all the previous reissues of BS&T II used the correct album mixes of the tracks.
Regarding Loggins & Messina's 'Full Sail', thanks to the help of some QQ members it looks like we've deduced that the initial pressings of the vinyl (incorrectly) credited only Al Lawrence (supervision) and Larry Keyes (remix) for this album, but later added Alex Kazanegras to both credits.
I believe this album was basically a 'quad handover' album - in an interview in 1975, Al Lawrence (who was CBS's 'Head Of Quadraphonic A&R') spoke of trying to convince bands to 'record in quad', ie have the original engineers do both the stereo and quad mixes rather than having one of their in-house guys (Larry Keyes, Don Young, etc.) do the quad mix after the fact. So I believe that Lawrence and Keyes assisted/instructed Kazenegras (who was L&M's main engineer) on the finer points of quad mixing, the two of them having done the quad mix of the self-titled L&M album the year before. You can see a similar pattern repeated with the Santana quad mixes - Lawrence and Keyes did the quad mixes of the first three albums, and then Keyes supervised Glen Kolotkin (Santana's engineer) for the remix of Caravanserai, and then Kolotkin did the quad mixes of the subsequent Santana albums (Welcome, Borboletta) on his own. The same happened with Kazanegras, who did the only subsequent L&M quad mix (Native Sons, in 1975) on his own.
I think it's also worth mentioning that the release of Full Sail augurs well for the unearthing of more missing/lost quad mixes, because when AF put out the quad mix of the self-titled Loggins & Messina album they said it was the only L&M quad mix Sony could find in their vaults. At the risk of sounding like a broken record (no pun intended, ha ha) when labels (especially enormous conglomerates like Sony) can't find something in their vaults it's infinitely more likely that it's just lost (either poorly catalogued or uncatalogued in a huge warehouse with a million other tapes) rather than having actually been stolen or destroyed. I hope that AF and other reissue labels like Vocalion continue to prove this theory of mine correct in the months and years to come.
Speaking of the quad version only, the mixes of the tracks from BS&T 'II' on BS&T 'Greatest Hits' are the same. The weird thing is that rather than both versions having the long album versions, it's the quad mix of BS&T 'II' that contains the single edits (ie the short version of Spinning Wheel etc). Even weirder is that Columbia definitely did a quad mix of the long album versions (it's out there on one of the Mike Robin reels) but chose to shelve it in favour of a mix that used the shorter single versions in their place. As someone else mentioned, the tracks from 'Child Is Father To The Man' will be different from the ones on the AF SACD released a couple of years ago because those were 5.1 remixes done by Al Kooper and the ones on the greatest hits are vintage quad mixes done by Mike Fusaro along with the rest of the album. Interestingly, BS&T Greatest Hits is the only album that Fusaro got a quad remix credit for, but you have to assume he did the quad mix of 'II' as well given that the tracks from II on Greatest Hits are the same mixes.
Probably of less interest to us but I assume the stereo layer of the Greatest Hits SACD will contain the single edits of the songs from BS&T II, which will mean it's the first time they've been issued, as the stereo layers of all the previous reissues of BS&T II used the correct album mixes of the tracks.
Regarding Loggins & Messina's 'Full Sail', thanks to the help of some QQ members it looks like we've deduced that the initial pressings of the vinyl (incorrectly) credited only Al Lawrence (supervision) and Larry Keyes (remix) for this album, but later added Alex Kazanegras to both credits.
I believe this album was basically a 'quad handover' album - in an interview in 1975, Al Lawrence (who was CBS's 'Head Of Quadraphonic A&R') spoke of trying to convince bands to 'record in quad', ie have the original engineers do both the stereo and quad mixes rather than having one of their in-house guys (Larry Keyes, Don Young, etc.) do the quad mix after the fact. So I believe that Lawrence and Keyes assisted/instructed Kazenegras (who was L&M's main engineer) on the finer points of quad mixing, the two of them having done the quad mix of the self-titled L&M album the year before. You can see a similar pattern repeated with the Santana quad mixes - Lawrence and Keyes did the quad mixes of the first three albums, and then Keyes supervised Glen Kolotkin (Santana's engineer) for the remix of Caravanserai, and then Kolotkin did the quad mixes of the subsequent Santana albums (Welcome, Borboletta) on his own. The same happened with Kazanegras, who did the only subsequent L&M quad mix (Native Sons, in 1975) on his own.
I think it's also worth mentioning that the release of Full Sail augurs well for the unearthing of more missing/lost quad mixes, because when AF put out the quad mix of the self-titled Loggins & Messina album they said it was the only L&M quad mix Sony could find in their vaults. At the risk of sounding like a broken record (no pun intended, ha ha) when labels (especially enormous conglomerates like Sony) can't find something in their vaults it's infinitely more likely that it's just lost (either poorly catalogued or uncatalogued in a huge warehouse with a million other tapes) rather than having actually been stolen or destroyed. I hope that AF and other reissue labels like Vocalion continue to prove this theory of mine correct in the months and years to come.
Not a great ELP record, but not a bad record, generally! 
