My 90 series handbrake takes an inch or two to fully apply especially if on a slope. My car is similar though not as extreme. Both use the same drum in disc type handbrake. Like others have said the handbrake on any Land Cruiser isn't the best in the world.
I have not adjusted my 90 series' handbrake before, but I have adjusted drum brakes on a trailer which have a very similar handbrake setup. Took lots of goes to get it functional so worth persisting with it for a bit longer if you don't have any of the issues above. Seems adjusted a fraction too much means a huge amount of drag, and not too much means the handbrake is useless.