For a really vague answer I would say that anything that makes you look closer at what you are doing is a good thing. I do feel I am making better guitars than I was before I started but I cannot attribute it totally to using the methods. It has helped me in one big way though. I am not a scientific thinker, I was an art schooler and firmly in the conceptual/creative side of my brain. Beginning to use the Chladni patterns was easier than some of the other methods for me because I was looking at shapes, it was a visual thing. And, subsequently, as I learn more about what the shapes mean I am starting to get a better grasp on the scientific reasons behind why they are what they are. Where it is leading me is in to paying more attention to the different resonances of the closed system. I don't feel like this discounts at all tuning the free plates but it is only one part of tuning the guitar. I think. So far.
Can you tell I'm not sure?
I am guessing that the soon to be DVD, coupled with a good reading if the available literature on the subject will give you an excellent place to begin from but Randy is correct in that the more you do it and the more records you have of your guitars the more you can gain from the results you have.
I hope that helps, If you have any other questions bring 'em on!