Oh dang ... I completely forgot ... sorry.
I looked at my local copy here and the mail function variables have hard-coded email addresses in there. So I looked at index.php where the mailing happens and I added some code to get the last record inserted and from that grab the email address entered by the person completing the form.
index.php on or about line 337 (added the code in bold just above the existing
[pre]
// execute the select query
$orig_details = execute_db($sql, $conn);
$row = fetch_row_db ($orig_details);
$emailcc = $row['Email'];
$insert_notice_email_cc_recipients_ar[1] = $emailcc;
$insert_notice_email_from_recipients_ar[1] = $emailcc;
$ntwktype = $row['Network'];
$res_details = execute_db($sql, $conn);
[/pre]
I've already set a insert_notice_email *recipients_ar[0] in my config.php so I set this one to [1].
For some of my more complex forms that have been requested, I use a script called Phorm to handle the complexities and mailing and stuff. In some cases it may be easier to build the custom form and then write the database insert code into that.