User ID field too small

I apologize if this has been addressed before, but I did do a search and did not turn up an answer.  I would like to use the users email address as his login because we are using it as the login to our main site and I want to pass it to wwf through the functions_member.asp, which I still can't get working, but have hopes I will.  The problem is the user ID field is not big enough to put in most normal emails, and I can seem to find a way to make it bigger.

I'm also a little confused about how to use the session variables to pass our own user login to wwf.  You pointed me last week to functions/functions_member_API.asp.    I must be doing something wrong, because I use session variables often to allow members access to certain pages, but can't figure out what I do with them in this instance.  Do you have a second to provide two or three lines as an example?