The VMCC brake trick for single leading shoe front brakes is to remove lining material from the trailing end of the trailing shoe: up to 2/3 of it.
Worked a treat on my Norton 8” SLS.
Home modifications to your brakes can be dangerous, of course, so I’m not advising anyone to do anything.
Been reading this thread with a lot of interest as I'm not at all happy with my standard brakes.
I can see how doing this could increase the mechanical advantage in the system, possibly allowing more force to be directed at the leading shoe and more pressure (force / area) over the reduced area in contact on the trailing shoe. Maybe this also helps the fabled self servo action to take effect, something that seems pretty elusive in my case.
I will hold off on going this far until I've skimmed my linings to match the drum dia and got full contact all over, then see how we go. I'm closer than when I started, at least the linings are actually contacting the drum now.