The problem arises when trying to adjust them using only the knurled wheel in the hubs. That is never going to work properly.
So you don't adjust them on the cable (which is logical, that's only to take unnecessary slack out of the cable) and you don't adjust them using the knurled wheel in the hub. I really am going to have to read the how-to again to find out exactly where you do adjust them!
It's about twenty years since I've had to adjust a handbrake. I think that's because I had Fords... 
Thats because you were probabaly driving lighter front wheel drive cars!
The auto adjusters on the rear shoe setup on the fords and Vx's work very well and require little attention......if the cable has some slack in it!
The Omega is much heavier and has a shoe setup that does the handbrake alone, this has a manual adjustemnt and in theory does not wear.
In reality it requires occasional maintenance (mine gets done every 2 years and always works well) and its worth just lightly applying the handbrake for 50m or so every month to remove any surface rust build up on the drum faces.
The adjustment is done via the adjusters on the shoes....but it must be done once you have made sure the cable is slack and that the pivots are all free.
Only once you have done this can you make any adjsutement to the cable.....and even when done this must have some slack when off to allow for suspension travel etc.
The optimum on the Omega handbrake is around 6 clicks to on.