I believe the GRF concept is fairly easy to understand but without some way of being able to measure pressure trace and all that, I think it has limited value or at least has limits depending on where you are in your golf swing journey as some have mentioned it has helped them even without being on plates/etc. So, to be fair I can only speak to my own experience so here it is...
First of all, I had heard the basics such as...
- you need to get pressure shifted back to your lead side earlier than you think (just after P2)
- before you start downswing, majority of pressure is at lead side
There are more commonly thrown around GRF nuggets but these two I think are pretty essential to using GRF to max potential.
Anyway.... I had practiced with that in mind for quite some time and thought I was doing pretty well... until I was able to measure it. I was able to try Bal.On inserts and in true "feel ain't real" fashion, I found out that I was nowhere close to where I thought I was. In fact I actually found out I was starting my backswing with a little shift to the lead side with pressure... never would have thought that. I picked up a pair of inserts and after a few weeks I was able to improve my pivot quite a bit. As a result some of the faults I had been working on improved as well.
It's not new ground but for me the moral of the story is that you need to verify what you think you are doing. That could be a qualified instructor or pressure inserts/plates (if you know how to interpret what they are telling you).