diff --git a/docs/LANES/LANE_C_NOTES.md b/docs/LANES/LANE_C_NOTES.md
index df47cb0..356c132 100644
--- a/docs/LANES/LANE_C_NOTES.md
+++ b/docs/LANES/LANE_C_NOTES.md
@@ -10,6 +10,12 @@ hangs off. **C owns the points + room fit; D owns occupancy truth; F owns the ha
 and every point walkable+reachable (or just trust C's asserts and check `.length` + that D's rig count ==
 `min(occupancy,3)`). Test page: the `path` overlay draws each point as a cyan post + facing nose.
 
+**Draw headroom for D's rigs** (I measured with 3 two-draw rig proxies standing at the points): worst
+interior in the `?stock=real` path is **68 draws** (opshop/hall) — browsers add ≤6, tons of room. The one
+tight spot is the *pre-existing* GLB-on worst (opshop/hall **344/350**, unrelated to browsers): if D's rigs
+are ever on TOP of GLB hero-props in that room, keep them impostor-cheap (≤2 draws each, the keeper pattern)
+and F's sweep-with-browsers should confirm ≤350. Everywhere else there's ample headroom.
+
 ### What C exposes on the room API (live once C1 commits)
 
 ```jsonc