The theory is one thing but a '72 Duster with a cast iron engine and stock suspension is such a horrible pig in terms of handling that theory doesn't apply.

If you want to learn handling theory then start with something nice and simple and square like an entry class pavement car. Something with a 50/50 weight distribution, rigid chassis and tuneable suspension at each corner. Then you can see what happens as you adjust spring rates, roll rates and shock valving.

A stock '72 Duster is a disaster and you have to stop the bleeding before you can even start to think about good handling. You need to add a bunch of roll stiffness just to keep the tires from folding over turning a corner. The stock tires are way too small for handling and the spring rate is way too soft. The weight distribution is horrible so it will never handle very good unless you spend money to take weight off the front.

So I'm not sure what answer you're looking for. If you want theory then there are plenty of books. If you want to make your Duster handle okay (like a new Honda Accord or something in that league) then ignore the theory and just call Firm Feel and do what they tell you do. If you want a daily driver where you can apply handling theory then sell the Duster and buy a used Z06 or something along those lines.