Thanks Audrey. I think I am going to go with a permeable tank divider for a while in the 4ft tank. I have had the female since Fall 2003, but the little male (and I am pretty sure its a male as it has an enlarged cloaca and is very long and lean, not pear shaped at all) I got from an individual who no longer wanted him this past July. He is only about half the size of the female in girth, but close to her length. I still think she could tear him apart, though, so they are not going to be allowed contact for awhile! I am planning on having lots of rock hides and plants as the male seems to like to hang out and hide in his plants (the female not so much). And I already mostly hand feed these guys now so I don't have to worry about finding and removing uneaten food later so I think that will help with any introductions down the road. I really appreciate your info. As soon as I can get my pair together I will post something.
Oh, and thanks Alejandro, I will check out that lead for the lid.