Some thoughts and ideas....
1) which RODS (men) do you want/need to be counter balanced and why?...
... if you are playing singles and shooting out of the back, then being able to put the 5-bar up and out of your way is the most important. so you could get by a little better by replacing those 5-man with coutnerbalanced ones, and be a "bit" better off.
... if you want the same "feel" on your offensive 3-bar when shooting a rollover or certain shot.. then you can get by with just upgrading those 3-men.
... it will get PRICEY quick like Sumner stated... but you can ease into an upgrade depending on what your main goals are. here's a link to our counterbalanced tornado men.
http://store.yahoo.com/foosdirect-store/fts-110-010-01.html 2) might some "brain surgery" help??? i haven't tried this... but it might be worth a shot... the "weight" in the men for the counterbalanced guys is pretty big and heavy.... how might you be able to converte non-balanced tornado man to a balanced one "consistently"... I'm thinking that if you drilled straight down into the top of the non-balanced tornado figure (dunno if you'd want it on or off the rod) with an appropriate diameter drill bit.. .then fill the hole with a heavy material.. .you might be able to come up with a consistent way to improve the balance on your exiting men. If you try this out..... let us know how it works!
JimW