Grinding the leading edge does take some skill and practicing on heads is a good idea. ideally, you could find someone with experience and have them each you how to do it. It is difficult to write in a few words what the process is and how to achieve the blended leading edge you’re looking for.
Below is a link to a Jet Multi-tool that would probably be the least you would need, with a combination of the correct belts, to be able to do some minor grinding on your irons.
There is also a video on our Youtube channel that we did that shows how to refinish soles of metal woods and irons, including taking scratches out, etc. I know that is not what your looking for, but it will show you the belts needed to grind and then blend and finish. I think you could get an idea of what would be involved by watching the iron part of the video. Again, it does not address grinding a leading edge, but you can use the sanding belt to remove material on the leading edge and then blend using the other belts shown. the link to the video is below:
If you would like to come to one of our schools sometime, I am sure we could carve out a few minutes to show you the process for actually grinding the leading edge of an iron.