Zappa's solo in Zoot Allures is from 1982 06 18 London.
ZA goes as follows: 0—59.03 19th early, 59.03—1.04.05 Frankfurt late, 1.04.05—2.04.62 19th early, 2.04.62—2.52.45 Frankfurt late again,—Rest 18th.
I am currently coming to the conclusion that almost the entire first part of Zoot Allures should be coming from Frankfurt 11th Late and nothing from London 19th early, except for the first 19secs portion which may be neither from Frankfurt nor from London, perhaps from a different, currently uncirculated 1982 concert (the bassline heard in London 19th or in any of my other 1982 AUD copies does not match with the Mother's Day version there, and in my Frankfurt copy the bassline in the first 19 secs is virtually inaudible), so no definitive concert date reference statement about that 0:00-0:19 portion from me here.
Please bear in mind that the drums in the Mothers Day version are "UMRK-Overdubbed" and therefore mostly different from those heard in the respective AUD recordings.
I asked Joe [Travers] which Helsinki show the Mothers Day download of "Cosmik Debris" was from and this was his reply...
23 August, 1973
Research, compilation and maintenance by Román García Albertos