The tornado rods are just a shade smaller to place in a fireball, 5/8 (15.875mm) vs 16mm, I'm confident they will work OK when used with new bearings but I personally think it a bad idea to introduce any sloppiness. I also consider a spare set of tornado rods a bad investment; I use fireball black rods with reamed/bored tornado figures...
Conversely the fireball rods will work in a tornado no problem but I have read some new rods might require a tiny bit of bearing shaving to spin freely. All my FB black rods fit with no mods into new tornado bushings..
I am not a high level player, so take the following advice with a grain of salt:
-I have a 3man goalie fireball, bought explicitly for the capability of tornado style play and easy bar removal (can be converted quickly to a side table and placed against the wall to keep my wife happy). As far as eyecandy goes, the blue play-field makes the game very appealing and modern looking. (think windows 7 vs pong) The fireball with tornado figures is close enough to a tornado to practice and provides the required feel.
-I learned on a tournament soccer table; yet I personally prefer the three man (3M) style. The corner ramps are something I consider slow and awkward. I do like both, but with a $1000 table, a flat playfield has more advantages in terms of repair, levelness, 1M conversion, and preparation for competition events. Cheap ramps and bar stops can be added for a crude approximation of a 1M goalie to either the 3M tornado or 3M-FB; you cannot convert a 1M sloped to a 3M. I suspect the fireball 1M is awesome with the seamless sloped bank... I'd love to try one... One came up for sale in Portland 4 month ago... I missed it by a day...
-I hate to say it again.... find a used tornado coin or TP3000... it is by far your best bet in Texas and will foster competition in your kids and their friends. And... If you really want you can stuff hard to find fireball parts on it if you really want later.