diff --git a/training/amygdala_training/train_steering_vectors.py b/training/amygdala_training/train_steering_vectors.py
index b44df2c..54603ab 100644
--- a/training/amygdala_training/train_steering_vectors.py
+++ b/training/amygdala_training/train_steering_vectors.py
@@ -850,8 +850,12 @@ def main() -> None:
     ap.add_argument(
         "--subspace-k",
         type=int,
-        default=20,
-        help="Top-k right singular vectors per story for subspace method",
+        default=512,
+        help="Max top-k right singular vectors per story for subspace method "
+             "(clamped to n_tokens per story). Default 512 is enough to span "
+             "each story's full natural subspace including per-attention-head "
+             "contributions on a hidden_dim=5120 residual stream. Smaller "
+             "values (e.g. 20) discard per-head discriminability.",
     )
     ap.add_argument(
         "--quality-report",