There is a Glype setting which allows you to limit the maximum file size of an individual download. For example, if the limit is 10MB, then a user will not be allowed to download any single file which is larger than 10MB.

To set a 10MB limit, edit inclides/settings.php from your Glype installation and find this line…

$CONFIG['max_filesize'] = 0

and change it to this…

$CONFIG['max_filesize'] = 10485760