More link URL's cut off at 128 characters because no max length is specified in the form field

If a URL is inserted in the More Link field on a views_box the URL is cut-off at 128 characters. This is because Drupal defaults the max length to 128 if no max length is specified.

To fix this, we just need to add a max length value to the More Link URL. For now, I am choosing an arbitrary number (max length = 500) that meets my needs. Question remains on what this number should be?