diff --git a/publications/comnet/experiments/analysis/figures/fig03_spike_iso_vs_topics.py b/publications/comnet/experiments/analysis/figures/fig03_spike_iso_vs_topics.py
index edc7f271..2efe8372 100644
--- a/publications/comnet/experiments/analysis/figures/fig03_spike_iso_vs_topics.py
+++ b/publications/comnet/experiments/analysis/figures/fig03_spike_iso_vs_topics.py
@@ -30,9 +30,13 @@ def load_topic_scaling_data(results_dir: Path):
             for run in RUNS:
                 filepath = exp02_dir / f"{transport}_loss1pct_run{run}.json"
                 if filepath.exists():
+                    try:
+                        with open(filepath) as f:
+                            result = json.load(f)
+                    except json.JSONDecodeError:
+                        print(f"  warning: skipping invalid JSON: {filepath.name}")
+                        continue
                     sources.setdefault(transport, {}).setdefault(8, [])
-                    with open(filepath) as f:
-                        result = json.load(f)
                     sources[transport][8].append(
                         result["results"]["windowed_correlation"]
                     )
@@ -46,11 +50,15 @@ def load_topic_scaling_data(results_dir: Path):
                         / f"{transport}_{topic_count}topics_run{run}.json"
                     )
                     if filepath.exists():
+                        try:
+                            with open(filepath) as f:
+                                result = json.load(f)
+                        except json.JSONDecodeError:
+                            print(f"  warning: skipping invalid JSON: {filepath.name}")
+                            continue
                         sources.setdefault(transport, {}).setdefault(
                             topic_count, []
                         )
-                        with open(filepath) as f:
-                            result = json.load(f)
                         sources[transport][topic_count].append(
                             result["results"]["windowed_correlation"]
                         )
diff --git a/publications/comnet/experiments/analysis/figures/fig14_strategy_comparison.py b/publications/comnet/experiments/analysis/figures/fig14_strategy_comparison.py
index 03802fab..d84a4087 100644
--- a/publications/comnet/experiments/analysis/figures/fig14_strategy_comparison.py
+++ b/publications/comnet/experiments/analysis/figures/fig14_strategy_comparison.py
@@ -44,8 +44,12 @@ def load_data(results_dir: Path):
             for run in RUNS:
                 tp_path = exp_dir / f"{strategy}_{topics}topics_throughput_run{run}.json"
                 if tp_path.exists():
-                    with open(tp_path) as f:
-                        d = json.load(f)
+                    try:
+                        with open(tp_path) as f:
+                            d = json.load(f)
+                    except json.JSONDecodeError:
+                        print(f"  warning: skipping invalid JSON: {tp_path.name}")
+                        continue
                     tp_values.append(d["results"]["throughput_avg"])
 
             if tp_values:
diff --git a/publications/comnet/experiments/parallel/common_parallel.sh b/publications/comnet/experiments/parallel/common_parallel.sh
index 2f9ee14a..a654b5ea 100755
--- a/publications/comnet/experiments/parallel/common_parallel.sh
+++ b/publications/comnet/experiments/parallel/common_parallel.sh
@@ -5,7 +5,24 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 ROOT_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
 
 : "${GROUP:?Set GROUP=1|2|3 before sourcing common_parallel.sh}"
+
+# The group env supplies defaults, but a value already set in the environment wins,
+# so `RUNS_PER_DATAPOINT=1 GROUP=1 bash parallel/foo.sh` behaves as written.
+_cfg_keys="BROKER_IP BROKER_SSH_IP PUB_IP PUB_INTERNAL_IP SUB_IP SUB_PROXY SSH_USER SSH_KEY_PATH RUNS_PER_DATAPOINT"
+for _k in $_cfg_keys; do
+    if [ -n "${!_k+set}" ]; then
+        eval "_preset_${_k}=\${${_k}}"
+    fi
+done
 source "${SCRIPT_DIR}/group${GROUP}.env"
+for _k in $_cfg_keys; do
+    _p="_preset_${_k}"
+    if [ -n "${!_p+set}" ]; then
+        eval "${_k}=\${${_p}}"
+        unset "${_p}"
+    fi
+done
+unset _cfg_keys _k _p
 
 : "${BROKER_IP:?Set BROKER_IP in group${GROUP}.env}"
 : "${BROKER_SSH_IP:=${BROKER_IP}}"
diff --git a/publications/comnet/experiments/run/02c_hol_topic_scaling.sh b/publications/comnet/experiments/run/02c_hol_topic_scaling.sh
index ee2e0497..83ece940 100755
--- a/publications/comnet/experiments/run/02c_hol_topic_scaling.sh
+++ b/publications/comnet/experiments/run/02c_hol_topic_scaling.sh
@@ -54,7 +54,7 @@ for tname in "${TRANSPORTS[@]}"; do
         label="${tname}_${topics}topics"
         echo "[${EXPERIMENT}] ${label}"
 
-        bench_args="--url ${url} ${flags} --mode hol-blocking --topics ${topics} --duration 30 --warmup 5 --payload-size 512 --rate 5000 --trace-dir /tmp/hol-traces"
+        bench_args="--url ${url} ${flags} --mode hol-blocking --topics ${topics} --duration 60 --warmup 5 --payload-size 256 --rate 500 --trace-dir /tmp/hol-traces"
         output_dir="${RESULTS_DIR}/${EXPERIMENT}"
         mkdir -p "$output_dir"
 
diff --git a/publications/comnet/experiments/run/common.sh b/publications/comnet/experiments/run/common.sh
index 7a6ecc53..b538c776 100755
--- a/publications/comnet/experiments/run/common.sh
+++ b/publications/comnet/experiments/run/common.sh
@@ -3,7 +3,24 @@ set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 ROOT_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
+
+# config.env supplies defaults, but a value already set in the environment wins,
+# so `RUNS_PER_DATAPOINT=1 bash run/foo.sh` behaves as written.
+_cfg_keys="GCP_PROJECT_ID BROKER_IP BROKER_SSH_IP CLIENT_IP REPO_URL REPO_BRANCH SSH_USER SSH_KEY_PATH RUNS_PER_DATAPOINT"
+for _k in $_cfg_keys; do
+    if [ -n "${!_k+set}" ]; then
+        eval "_preset_${_k}=\${${_k}}"
+    fi
+done
 source "${ROOT_DIR}/setup/config.env"
+for _k in $_cfg_keys; do
+    _p="_preset_${_k}"
+    if [ -n "${!_p+set}" ]; then
+        eval "${_k}=\${${_p}}"
+        unset "${_p}"
+    fi
+done
+unset _cfg_keys _k _p
 
 : "${BROKER_IP:?Set BROKER_IP in config.env}"
 : "${BROKER_SSH_IP:=${BROKER_IP}}"
@@ -63,11 +80,11 @@ restart_broker() {
 apply_netem() {
     local delay_ms="$1"
     local loss_pct="${2:-0}"
-    ssh_client "sudo bash /opt/mqtt-lib/experiments/netem/apply.sh ${delay_ms} ${loss_pct}"
+    ssh_broker "sudo bash /opt/mqtt-lib/experiments/netem/apply.sh ${delay_ms} ${loss_pct}"
 }
 
 clear_netem() {
-    ssh_client "sudo bash /opt/mqtt-lib/experiments/netem/clear.sh"
+    ssh_broker "sudo bash /opt/mqtt-lib/experiments/netem/clear.sh"
 }
 
 MONITOR_PID=""