I'm gonna have to disagree with Nokton48, I would not have the camera circuitry adjusted. I have used a Chris(sp) adapter with the silver battery in an SRT I rebuilt and the meter was spot on. The adapter and silver battery work in place of the 1.3V mercury 625 battery.
About ten years ago I had a Canon F-1 rebuilt and the tech changed the circuitry as Nokton48 described. The camera meter is now next to worthless. The Eveready #357 batteries start out at about 1.5V (which is what the tech will set the circuitry to match), but unlike the mercury batteries, and the silver batteries, the #357 immediately starts losing power, and declines throughout its life. So the meter may be accurate when you first put the battery in, but then it gets progressively more inaccurate as the battery drains. And there is no way to fix that.
Again, I would NOT have the camera's circuitry changed. Put out the money for the Chris (sp) adapter and silver battery, and your SRTs will have accurate meters.
Best,
-Tim