Just donated enough for you to have a beer on me, wish it could be more, but I do admin my vanilla site as an unpaid volunteer... THANK YOU for your many contributions around this place. I have found your posts very helpful whilst taking the leap and upgrading to 2.1.
Karen, thank you for the kind feedback and donation. always nice.
you might find these two plugin handy as well for your particular forum.
Also, to stop spam applicants
addregistrationquestion is a better, cleaner plugin then botstopapproval.
and for getting a handle on your user stats. (my favorite plugin )
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.