Specifying the path to the application is commmon as most servers don't have their sbin in their "path".
As for specifying -t, I'd add it IF the normal code shows it, as it scans the to: cc: and bcc: lines for addresses to send users (as bcc is how you mail numerous users without them all seeing eachothers email addresses).
As for -i i'm not sure what it's for, but again if it's in the ubb already i'd say to leave it...
