With a few modifications, like stealing Lonks use of a (instead of " ") as a separator, which was very smooth, here's an updated version of Allens's code with a score 233

Code:

function f($)
  dim $h,$c,$o,$t,$a
  $f=ubound($)
  do
    $h=$c+1
    do
      $a=$[$c]+$[$h]
      if len($a)=2*len(join($,""))/($f+1)
        $o=$o + a +$a+ a+ $[$h]+$[$c]
      endif
      $h=$h+1  
    until $h>$f
    $c=$c+1
  until $c=$f
  for each $ in split($o,a)
    $h=ubound(split($o,$))
    if $h>$t
      $t=$h
      $f=$
    ;endif
  ;next
endfunction