Ah - well with a King the chamfers on the races are very small, so I've found they need to be 'overtight' to be tight enough for a trials bike (which is why I went off them a few years back). Fine on an XC bike as you aren't ragging the hell out of the bars/forks all the time, but mine was a bit of a pest on my trials bike unfortunately.
The top wedge also isn't split, so they don't compress and grip your steerer when you tighten them down, meaning you need to get a lot of torque in the top cap bolt to make them feel tight. I would probably go with the 'nip top cap down then turn stem to tighten some more' system you've been using in the past