Most Ibanez guitars I've owned that have tremolos have needed some slight adjustment to the bridge radius and my Jem is no exception. Ibanez tremolos are really nothing more than soft, die-cast "pot-metal" that is molded much like Hot Wheels toy cars. It's unfortunate that Ibanez uses such inferior metal in their bridge parts, since I am sure tone must be adversely affected as a result. Often during molding processes, cheap pot-metal parts like these are not created at high tolerances, and therefore it is relatively common to see Ibanez bridge saddles not conforming to the exact radius of the bridge plate itself.
I bought this guitar new years ago, but I am just now getting around to fixing the bridge radius. It was only slightly off, so I was in no real hurry to correct it... I had many more pressing repairs that needed to come first. But today I was in the mood to fix it. :)
There were two saddles that were off... the high E was a fraction low and the D saddle was too high. To raise the high E saddle I cut a piece of 0.1 millimeter brass nut shim to the exact shape of the bottom of the saddle and reinstalled the saddle with the shim underneath. This was just the perfect amount needed to bring the high E saddle up to the same level as the B, G, A and low E saddles. Next up, lowering the D saddle.
To lower the D saddle I first removed it from the bridge, then carefully sanded the bottom of the saddle by hand to get the desired height. The only real way to do this effectively is to sand a little at a time, reinstall and check the height. I had to do this many times before I got the height just right. The trick is not go too far and take off too much. That is why it is so important to go slowly and check the height often before you've lowered it more than needed.
A quick check with the radius gauge confirmed that my job was complete. I certainly won't notice much of a difference since neither of these saddles were so far off that my picking mechanics would have been affected, but it is nice to know that the radius is correct and the guitar is setup as perfectly as possible.