I don't use the scales to get the car to 50/50 but rather make sure it is as even as possible between left and right. If you are a bit heavier in the rear don't worry about it too much. I wouldn't want more weight in front though. If you find that 50/50 isn't working well for you, go a bit more rear biased and try again.

Since I run 2WD buggies, my cars are very rear biased and there is a lot of weight in the worst possible place which is outside of the wheelbase. In this case at the rear. I added more weight to my car down the center between the wheelbase. Yes I added a noticeable amount of weight but the amount of weight behind the rear axle is now less of the total weight than it was before which in my case made everything much better.

Once you get the shocks and springs balanced and setup how you like them, tune your cornering ability with "roll center" tuning. A rear weight biased vehicle needs more rear roll stiffness than the front. After realizing that the rear has to be stiffer in springs, this should seem obvious. A more equal the weight bias is, the more even the "roll centers" should be. In my case when I accelerated out of corners, the inside front wheel came off the ground. That's not very good for cornering power and led to huge amounts of understeer. I am running a higher roll center in the rear which is seen as greater camber gain. The front runs a lower roll center which is seen as less camber gain. It wasn't quite enough though. I needed a roll bar in the rear to help make up that last bit of rear roll stiffness. The car corners very hard now. I was going to run a much lower rear roll center but it would have required a much stiffer rear roll bar and that messes up other things. It's all a compromise.

Stick with it. Be patient. You'll get it and trust me when I say, you'll love it when you do!