I read that all his guitar tracks were live takes. He hated playing in the studio so they would tour, do the songs and take an isolated track of his guitar to add to the studio recorded tracks later.
“he hated playing in the studio”
Zappa’s studio was his home. He lived and breathed studio.
Zappa liked his improvisations while playing live. So he constantly recorded multitrack on all his shows.
He was also known to take Solos from song A and apply them to song B. He mixed and mashed live recordings.