Thanks for sharing this. Although, I was hoping for some secret trick, unfortunately, the technique is similar to what many HG-1 customers have discovered on their own.
I apologise in advance for sullying your helpful post, with my bad experience, but I feel that it is important to share it.
I've had the HG-1 for a few years, and have stopped using, due largely in part that it's so difficult to align. I've tried the light gap technique, I've tried grinding onto a piece of paper to get a level and consistent 'donut' of grounds; I've even go so-far as to use a set of feeler gauges. It's a fools errand, no matter, and the grind still has a lot of boulders.