Some backyard experience: The battery and the driver on the left pretty much account for the extra left side weight. My '94 right front was lighter by about 90 pounds (with me included.) Before I had adjustable sleeves on the shocks, I had shaved the upper spring seats to lower the car. A little measuring and Kentucky windage, and if the right rear shock spring seat was cut an additional 0.25" vs. the left rear (wedge to add weight to LR and RF), you dial out a big chunk of the right side tire sliding. And since you'd have the rear end of the car up (you might be putting on new brakes?) you're right there anyway. Janni's ride height tuning can provide another data point for how much different left to right should be.
Not to toot my capitalistic horn, but the rear brake swap will be a big change and the corner weight is a tuning change (which will be affected by carrying passengers.) And by all means, if there's something wrong, it needs to be fixed.
Note: depending on the use of the OEM proportioning valve or not, with the 40mm rears, the fronts will lock either "just barely before" to "really close to the same time" as the rears. Things like road surface, turning, tires, brake pads, etc, will become bigger factors in deciding.
Hmmm... he says. Maybe an appropriately cut down spring seat would make another option to improving Viper braking!