grayco If it's outside public_html (ie WHMCS crons for pop.php cron.php etc) we used the full path with the /var/www/USER_UUID/ prefix you indicated, but for general crons inside public_html we just start with public_html/path_to/file.php and that works fine.
You can also use '/usr/bin/php -q' or the 'php -q' interpreter and either should work.
As a side note if anyone is using wget crons you should note that it doesn't work until you add quotes around the URL, but there is a bug where you can't actually add the quotes until you first add the URL, and then go back and edit it and add the quotes. If you get an error from Enhance saying it has to start with http:// or https:// that is the problem. This should be fixed in a future update and automatically add the quotes for you.