You might wanna check out
/help /iline, that will insert a line where ever you want. so something like:
...
window @Msg.Spam Trebuchet MS 13
[color:red]iline[/color] -p @Msg.Spam [color:red]1[/color] 3 $timestamp $+ < $+ $nick $+ > $1-
...
would add the line to line 1 of @Msg.spam