According an interview that Dick Clark did, they taped three Bandstand episodes on Saturday and three more on Sunday, every 6 weeks. In terms of Pyramid, that varied. In the 70s, he taped five shows on Tuesdays and five more on Wednesdays, when necessary. For the 80s versions, he taped five $25,000 shows on Tuesday, five more on Thursday and five $100,000 shows on Friday.
In terms of subs on Bandstand in the Pyramid years, only Donna Summer ever guest-hosted. Even then, Dick was still on that episode.