Series drift is usually blamed on the model. Look at the page instead. The character was described from memory at every job, and memory sketches her a little differently each sitting. “Copper-red waves with a tortoiseshell clip” in frame one becomes “red elegant hair” by frame four, and the audience watches a stranger take her place. The repair is clerical: enter her once, in an atelier ledger you paste rather than retype.
Five fixed lines, always in order
Age — a number, and in this atelier a mature one. Hair — colour, length and one habitual style. Build — two or three words, no more. Face — one or two details that survive any light. Signature — the one object or mark that identifies her at a glance.
One page, every bench
The ledger stays open on the worktable for the whole set. Generator, video bench, editor and swap all read the same page, so a disagreement between frames is settled by the page, not by taste. That is the whole secret of a coherent series, and it costs nothing but the habit.