ie if you do /oneway % message .. and there are 4 % in channel .. it wil echo 4 times. i havent been able to fix this yet despite my efforts. if anyone can help please.
just remove your echo from loop and put it befor the last "}"

alias oneway {
  var %i 1
  while $nick(#,%i,$1) {
    .notice $v1 [ $+ viewable only by channel rank $1] $2-
    inc %i
  }
  echo -a $me oneway message for all  $1 - $2-
}