Charles' song ("Which of the Pickwick Triplets did it") was 2 minutes and 46 seconds long, which is the length that Oliver expected it to be.
"sitzprobe" is from the German words "sitz" (sit) and "probe," (rehearsal). During a sitzprobe the cast and orchestra run through the performance together for the first time.
The names of the triplets in Oliver's play are Penelope, Patrick, and Paco.