For T jets, especially with the twitchier older JL/AW chassis, 90 ohm or better Parma econo controllers are the best bang for the buck. When all your set controllers are in the 45-60 ohm range this is the simplest solution to better control.
The best Ohm level for those cars will depend upon how you are powering your track. If you are using 12-18 volts a 45 Ohm controller should work for magnetractions while nonmags would likely prefer 60-90 Ohms. If you are using higher voltage, then 60-90 Ohms would be best. Overall, I've found that 60 Ohm Parma econos work for a wide variety of cars and voltages. They're not always ideal, particularly for higer downforce cars like Marchons, but they'll work and if all four lanes are using the same controllers a 60-Ohm Econo is a reliable, economical choice.
On my own little experience of home racing, I found that a controller choice depands on :
chassis you will run
voltage on your track
Personaly, on my track, I'm running around 13volt, 8amperes (powering 4 lanes), and mostly xtractions and tjets (+ a couple of magnetless inline chassis like tyco 440 widepan, and a few tomy turbos and 440narrow with magnet). I found that 45ohm was a bit too short for my needs. I plan to upgrade to parma eco 60ohm controllers.
Does it worth the investement ? In my opinion, definitly. At least 1 for you, and give cheap controllers to your opponents