diff --git a/scripts/tc-ads-watch-10min.ps1 b/scripts/tc-ads-watch-10min.ps1
new file mode 100644
index 0000000..c206a3d
--- /dev/null
+++ b/scripts/tc-ads-watch-10min.ps1
@@ -0,0 +1,24 @@
+$ErrorActionPreference = 'Stop'
+$adsDll = 'C:\Program Files (x86)\Beckhoff\TwinCAT\3.1\Components\Base\v170\TwinCAT.Ads.dll'
+Add-Type -Path $adsDll
+$c = New-Object TwinCAT.Ads.TcAdsClient
+$c.Connect('169.254.176.217.1.1', 851)
+function ReadSym($name, $type) {
+    $h = $c.CreateVariableHandle($name)
+    $v = $c.ReadAny($h, $type)
+    $c.DeleteVariableHandle($h)
+    return $v
+}
+$prev = $null
+for ($k = 1; $k -le 10; $k++) {
+    $nc  = ReadSym 'GVL_Sync.nCycles' ([uint64])
+    $bs  = ReadSym 'GVL_Sync.bSync' ([bool])
+    $nrs = ReadSym 'GVL_Sync.nReturnedSeq' ([uint64])
+    $nm  = ReadSym 'GVL_Sync.nMismatch' ([int])
+    $lag = [int64]$nc - [int64]$nrs
+    $delta = if ($null -ne $prev) { $nm - $prev } else { 0 }
+    $prev = $nm
+    Write-Host ("{0,2}  nCycles={1,-8} lag={2,4}  bSync={3}  nMismatch={4}  delta={5}" -f $k, $nc, $lag, $bs, $nm, $delta)
+    if ($k -lt 10) { Start-Sleep -Seconds 60 }
+}
+$c.Dispose()
diff --git a/src/main.rs b/src/main.rs
index 850ec54..911b28e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -758,8 +758,8 @@ async fn run(cfg: &Config) -> Result<(), Box<dyn std::error::Error>> {
     // Async pipelined FPWR: two alternating leaked tx slots so the in-flight
     // write future can hold a 'static buffer while the response is reaped
     // at the start of the next cycle.
-    let tx_slot_a = Box::leak(Box::new([0u8; 8]));
-    let tx_slot_b = Box::leak(Box::new([0u8; 8]));
+    let tx_slot_a = Box::leak(Box::new([0u8; PAYLOAD_LEN]));
+    let tx_slot_b = Box::leak(Box::new([0u8; PAYLOAD_LEN]));
     let mut tx_slot_toggle = false;
     let mut pending_tx: Option<
         std::pin::Pin<Box<dyn std::future::Future<Output = Result<(), ethercrab::error::Error>> + '_>>,
@@ -939,7 +939,7 @@ async fn run(cfg: &Config) -> Result<(), Box<dyn std::error::Error>> {
                 tx_buf[264..268].copy_from_slice(&(jitter_ns as i32).to_le_bytes());
             }
 
-            if spin_mode && PAYLOAD_LEN == 8 {
+            if spin_mode {
                 // Async pipelined FPWR: kick the frame onto the wire now
                 // (poll_once drives it to sendable), reap response next
                 // cycle. Frees ~240us of blocking write time per cycle.