Retime/Compositor (AE/Resolve/Nuke) — kill 8 seam hitches (40 sec) on 9:16 AI loop (no hitch @ 0.25×)

Project: 8×5s Seedance clips → 20–40s 9:16 loop. Joins show: baked head/tail easing (“speed-bump”), micro gamma/WB drift, slight endpoint variance. I need an invisible loop with constant forward motion.

Your job: Time-remap S-curve across each join (±2–4% over ~12–24f) to remove settle/re-accel.
Masked optical flow in a 6–12f overlap only (no particle “melt”).
Per-clip trims under a global WB/Gamma layer; single grain plate over the full timeline.
No zooms/reframes, no UI/text. Keep optics natural.
Build a small “Seam Module” (precomp/macro) with exposed sliders: OverlapFrames, FlowMix, DissolveFrames, MaskFeather, GammaTrim, WB, Grain.

Template deliverable (so I can do it myself later)
AE or Resolve template (“Seam Module”) with exposed sliders: OverlapFrames, FlowMix, DissolveFrames, MaskFeather, GammaTrim (Levels Gamma), WB (Temp/Tint), GrainStrength.
Project structure: 9:16 720/1080p master, global WB/Gamma adj layer, single grain plate, per-clip trims underneath; drop-zones clearly labeled (A_tail, B_head).
Presets/macros:

AE: .ffx for the time-remap S-curve; if Twixtor is used, include exact settings + a Pixel Motion fallback.
Resolve: Fusion macro (optical flow + mask node tree) + Deliver preset.
Compatibility: AE 2023+ (no paid plugins unless pre-approved) or Resolve 18.6+ (Speed Warp OK).
README (1 page): step-by-step seam workflow + QC checklist (0.25× check, scopes, difference matte).
Screen capture (5–7 min): show diagnosis → build overlap → masked optical flow → S-curve → grade match → QC. (No VO needed, on-screen notes OK.)
Replicability test: I must be able to reproduce one seam in ≤45 min using your template. If not, you tweak the template until I can.

QC (pass/fail)

Playback 0.25×: no hitch at joins.
Waveform/Histogram: no step change across cuts.
Difference matte last 12 vs first 12 frames on the loop: average delta ≤ ~2%.

Tags/keywords: After Effects, DaVinci Resolve, Nuke, Twixtor, Speed Warp, Pixel Motion/Timewarp, optical flow masking, time-remap S-curve, difference matte, film grain, 9:16, seamless loop.