diff --git a/analyze_spin_ab_urus.py b/analyze_spin_ab_urus.py
index f01dfd5..b193d5d 100755
--- a/analyze_spin_ab_urus.py
+++ b/analyze_spin_ab_urus.py
@@ -18,7 +18,10 @@ import os
 import re
 import sys
 
-GATED = {2, 4}  # core counts where the RFC 004 spin policy is active
+def gate_active(cores):
+    """RFC 004 spinner cap is non-zero only at 2..=4 schedulers (1 and >=5
+    allow 0 spinners), so the policy is active exactly there."""
+    return 2 <= cores <= 4
 
 
 def parse_latency_ms(s):
@@ -88,7 +91,7 @@ def main():
         b = fnum(before.get(k, {}).get("sustained_rps"))
         a = fnum(after.get(k, {}).get("sustained_rps"))
         spd = f"{a / b:.2f}x" if (a and b) else "—"
-        gate = "ACTIVE" if cores in GATED else "inert"
+        gate = "ACTIVE" if gate_active(cores) else "inert"
         bs = f"{b:,.0f}" if b is not None else "—"
         as_ = f"{a:,.0f}" if a is not None else "—"
         print(f"{srv:<10} {scn:<4} {cores:>5} {bs:>12} {as_:>12} {spd:>8}  {gate}")
@@ -107,7 +110,7 @@ def main():
                 delta = f"{(a - b):+.2f}"
             else:
                 delta = "—"
-            gate = "ACTIVE" if cores in GATED else "inert"
+            gate = "ACTIVE" if gate_active(cores) else "inert"
             bs = f"{b:.2f}" if b is not None else "—"
             as_ = f"{a:.2f}" if a is not None else "—"
             print(f"{srv:<10} {scn:<4} {cores:>5} {bs:>10} {as_:>10} {delta:>9}  {gate}")
@@ -126,8 +129,10 @@ def main():
 
     print(
         "\nReading it: spin is 'worth it' if s3 (and/or s2) RPS rises and/or "
-        "tail latency drops at cores 2/4 (gate ACTIVE), with cores 1/8 (inert) "
-        "staying flat. Flat-or-worse at 2/4 = not worth it on real traffic."
+        "tail latency drops at the gate-ACTIVE cores (2-4), with the inert "
+        "controls (1 and >=5, e.g. 6) staying flat. Flat-or-worse at 2/4 = "
+        "not worth it on real traffic. Cross-check that the saturating control "
+        "(6 cores) is actually CPU-bound, not loadgen-bound, before trusting it."
     )
     if "axum-mem" in {k[0] for k in keys}:
         print(
diff --git a/spin_ab_urus.sh b/spin_ab_urus.sh
index 4a8515c..61cdd74 100755
--- a/spin_ab_urus.sh
+++ b/spin_ab_urus.sh
@@ -20,10 +20,13 @@
 # Scenarios (per RECON §6.4): s2 (router+auth, no store) and s3 (memory store,
 # the headline). Server is urus-mem for both. We do NOT touch s4/sqlite.
 #
-# Core sweep (per RECON §6.3): the spin gate is active at 2-4 schedulers and
-# inert at 1 and >=5, so 2 and 4 should show the effect and 1 and 8 bracket it
-# as controls. Server is pinned to cores 0..N-1; the load generator gets its
-# own disjoint cores (LOADGEN_CPUS).
+# Core sweep: the spin gate is active at 2-4 schedulers and inert at 1 and
+# >=5. We sweep 1/2/4/6 server cores: 2 and 4 are gate-ACTIVE, 1 and 6 are
+# inert controls -- 6 also being a *saturating* control, since the old 8-core
+# point couldn't be saturated by an 8-core loadgen (it plateaued ~102k rps,
+# loadgen-bound). Server is pinned to cores 0..N-1; the load generator gets
+# its own disjoint cores (LOADGEN_CPUS), sized ~>=2x the server cores per the
+# saturation goal while leaving cores free for the OS.
 #
 # Usage:
 #   ./spin_ab_urus.sh                      # full A/B, defaults
@@ -37,8 +40,10 @@
 # Env knobs (all overridable):
 #   BEFORE / AFTER     smarm commit-ishes              (default b0c9685 / HEAD)
 #   SCENARIOS          space-separated                 (default "s2 s3")
-#   CORES              server core counts to sweep     (default "1 2 4 8")
-#   LOADGEN_CPUS       loadgen taskset range           (default "12-19")
+#   CORES              server core counts to sweep     (default "1 2 4 6")
+#   LOADGEN_CPUS       loadgen taskset range           (default "8-23" = 16 cores)
+#   WRK_THREADS        loadgen wrk/wrk2 threads         (default 16)
+#   WRK_CONNS          loadgen open connections         (default 512)
 #   SERVER             memory server backend           (default urus-mem)
 #   PROBE_SEC/WARMUP_SEC/MEASURE_SEC/SAT_RATIO/PREPOP/WRK_CONNS/WRK_THREADS
 #                      passed straight through to runner.sh
@@ -74,9 +79,15 @@ AFTER_DEFAULT="$(git -C "$SMARM_DIR" rev-parse --short HEAD)"
 AFTER="${AFTER:-$AFTER_DEFAULT}"
 
 SCENARIOS="${SCENARIOS:-s2 s3}"
-CORES="${CORES:-1 2 4 8}"
+CORES="${CORES:-1 2 4 6}"
 SERVER="${SERVER:-urus-mem}"
-LOADGEN_CPUS="${LOADGEN_CPUS:-12-19}"
+LOADGEN_CPUS="${LOADGEN_CPUS:-8-23}"
+
+# Loadgen sizing: ~2x loadgen cores per server core. 16 cores covers the
+# 6-core server at ~2.7x and the 4-core at 4x. Threads track the core count;
+# connections bumped so the probe can actually find the server's peak.
+export WRK_THREADS="${WRK_THREADS:-16}"
+export WRK_CONNS="${WRK_CONNS:-512}"
 
 QUICK=0
 DRY=0
@@ -111,7 +122,8 @@ echo ">>> smarm:     $SMARM_DIR"
 echo ">>> BEFORE=$BEFORE  AFTER=$AFTER"
 echo ">>> servers:   ${SERVERS_TO_RUN[*]}"
 echo ">>> scenarios: $SCENARIOS"
-echo ">>> cores:     $CORES   (loadgen on $LOADGEN_CPUS)"
+echo ">>> cores:     $CORES"
+echo ">>> loadgen:   cpus=$LOADGEN_CPUS threads=$WRK_THREADS conns=$WRK_CONNS"
 echo ">>> machine:   $NPROC cores"
 echo ">>> outdir:    $OUTDIR"
 [[ "$QUICK" == "1" ]] && echo ">>> --quick: probe/warmup/measure = ${PROBE_SEC}/${WARMUP_SEC}/${MEASURE_SEC}s"