FICTIONAL DEMO WORKBACK — revised v2
Outcome at T0: demonstrate ONE agreed workflow with prepared sample data after rehearsal. The second workflow is excluded; this is not a production-readiness claim.
Owner: one builder. B and C each require full attention; do not overlap them.
Time convention: T0 = demo start. T-4 to T-3 is one full WORKING day. Use a declared working calendar; map to dates only after confirming hours, holidays, availability, timezone and exact cutoff.
Available interval: T-10 to T0.

A: agree narrower scope | 1 day | T-10 to T-9 | no predecessor
Done: one workflow agreed; second workflow explicitly excluded.
B: build narrower prototype | 3 days | T-9 to T-6 | needs A
Done: agreed path runs. Three-day estimate depends on accepted scope reduction.
C: prepare sample data | 2 days | T-6 to T-4 | needs A; follows B for owner capacity
Done: data matches the agreed path.
D: assemble demo | 1 day | T-4 to T-3 | needs B AND C
Done: prototype and data work together.
E: rehearse | 2 days | T-3 to T-1 | needs D
Done: complete run; remaining issues resolved or explicitly disclosed.
BUFFER: 1 day | T-1 to T0 | record use and remaining allowance.

Total: 1 + 3 + 2 + 1 + 2 + 1 = 10 working days.
Original scope needed 11 with one owner; nine days assumed independent B/C capacity.
If the three-day prototype estimate is not credible: reconfirm scope, a qualified second owner, or a later demo date. Do not silently overlap full-attention tasks or delete rehearsal/buffer.
Still to fill for real use: authoritative event reference, actual dates, timezone/cutoff, calendar exceptions and scope approval reference.
Change rule: revise detailed schedule first; then update any day countdown. Readiness follows handoff evidence, not the countdown value.