Many onroad cars come with 2 small holes in the chassis F/R.
I put the same two holes in all my off road RC's.

With no tires, setting on the points (you can make them yourself) move your stuff around for your static balance side to side, a small bubble level will be needed on the chassis.

Then put the tires on and use one point and two scales so your only looking at one end at a time, keep the chassis level at all times.

At this point add the two scales together for the front and rear, also move your weight around more.
After you try doing it this way you'll get a better idea how to tell where the weight needs to go F/R.