Joe,
I dislike adding nonfunctional lead to anything made out of balsa wood. It just seems that gravity already wins more than it's share of our battles, I hate to give it any more help than I have to! ;-)
But, with that said, I too have run into the same problem with some of my IC powered planes. My Flite Streak now flys with it's tail weight lead replaced by a nice looking, functional, and relatively heavy R/C type tail wheel assembly. And it looks better than the lead it replaced, a little pretentious, but better. ;-)
All the previous imaginative suggestions will work perfectly, and they all will look better than the square weights, attached with a servo screw, that I used to have my plane. ..... My guess is that your next Twister will have an even longer aft fuselage? :-)