Just looked at the recipe. Are you using six-row? If so you can do a short protein rest. I would shoot for 127°-128° for about 15 minutes.
Why would you want to add corn to the boil? One reason we boil is to drive off DMS. DMS provides a creamed corn flavor to the finished beer. Six-row contains more SMM (precursor to DMS) so I would think you would want to avoid adding corn to the boil.