Duh! That worked.

I wrote a vbscript that runs in Windows that will toggle that "once = 1" flag like so

once = 1 to --once = 1
and
--once = 1 to once = 1

It expects multi-core client setups with the following folder structure
Example:
C:\dcprojects\llrnet (can be anywhere) This is where the vbscript goes - I called it Toggle_Work.vbs
Inside that directory, it expects to see the following directory names, all starting with llrnet - for multi-core setups.
llrnet1
llrnet2
llrnet3
...
llrnet8

It will edit each llr-clientconfig.txt in each directory that starts with LLRNET (case not sensitive)

If you used some other directory name, change the code where it shows LLRNET to whatever you used
In the below code, look for: strFolder = objShell.CurrentDirectory & "\LLRNET" & count & "\"
or, rename your directories

If you have more than 8 cores, say 16, look in the code for
For count = 1 to 8
and change it to
For count = 1 to 16

Give it a go and let me know what you think.

Because the forum 'code' tag screws stuff up, I'll place the vbscript code in php tags

FileName: Toggle_Work.vbs
PHP Code:
'Option Explicit
Const ForReading = 1
Const ForWriting = 2

Dim objShell, objFSO, objFile, FileName, count, strFolder, strLine, strNewText, strFlag
Set objShell = CreateObject("Wscript.Shell")
FileName     = "llr-clientconfig.txt"

pcengine = LCase(Mid(WScript.FullName, InstrRev(WScript.FullName,"\")+1))
If Not pcengine="cscript.exe" Then
    Set WshShell = CreateObject("WScript.Shell")
    WshShell.Run "CSCRIPT.EXE """ & WScript.ScriptFullName & """"
    WScript.Quit(1)
End If

WScript.Echo vbCrLf

On Error Resume Next
For count = 1 to 8
    strFolder = objShell.CurrentDirectory & "\LLRNET" & count & "\"
    Set objFSO = createobject("Scripting.FileSystemObject")
    If objFSO.FolderExists(strFolder) then
        Set objFile = objFSO.OpenTextFile(strFolder & FileName, ForReading)
        Do Until objFile.AtEndOfStream
            strLine = Trim(objFile.ReadLine)
            If InStr(1, strLine, "once", 1) Then
                If strFlag = "" Then
                    strLine = Replace(strLine, " ", "")
                    If Left(strLine, 2) = "--" Then
                        strLine = "once = 1"
                        strFlag = "once = 1"
                    Else
                        strLine = "--once = 1"
                        strFlag = "--once = 1"
                    End If
                Else
                    strLine = strFlag
                End If
            Else
            End If
            strNewText = strNewText & strLine & vbCrLf
        Loop
        objFile.Close
        If strNewText = "" Then 
            WScript.Echo "There is a problem with " & FileName & " aborting!"
            Exit For
        End If
        arrLines = Split(strNewText, vbCrLf)
        Set objFile = objFSO.OpenTextFile(strFolder & FileName, ForWriting)
        For i = 0 to UBound(arrLines) - 1
            objFile.WriteLine arrLines(i)
        Next
        objFile.Close
        WScript.Echo "llrnet" & count & " changed to " & strFlag
        strFolder = ""
        objFSO = ""
        objFile = ""
        strLine = ""
        strNewText = ""
        arrLines = ""
    Else
    End If
Next
WScript.Echo VbCrLf & "Sleeping for 5 seconds..." & vbCrLf
WScript.Sleep(5000) 
Enjoy