The only and proper way to adjust the steering box is to have it completely separated from the steering shaft as well removed the drag link from the pitman arm.
I'd give anyone a 99% chance they end up over tightening the box while its still attached to the steering shaft and drag link.
The tight spot is in the straight ahead direction with a little slack going off center left or right.
Like I mentioned above everything removed then your able to detect a slight amount of added drag or resistance passing over the straight ahead zone while turning the input shaft, once established snug the lock nut and leave alone.
Must also mention the first adjustment is to the input shaft first then the sector shaft last.
BTW, I was shocked to see LR purchased the rights from Ford as that same design steering box LR use was a 1 1/2 year Ford wonder, actually a failure by design Ford found out as well myself with the 68 F250 truck. Called a Bendix box. I made it to 69K original miles then the input shaft (weak bad designed item) began to leak. Rebuild kits $158 each then becoming NLA by Ford or anybody. Second seal kit already added an oil cooler not the crappy looped tubing in frame Ford used, yup failed again.
Already a twitchy box like driving a go cart at 80 mph plus rebuild shops hated them, most were shot being over 40 years old plus rare no good cores to rebuild. They were a later conversion item for those seeking PS vs manual Ford trucks back in late 67's for the earlier truck. By 69 Ford went with a Saginaw box, very common, much cheaper to rebuild plus lasting 300K trouble free service miles and without that twitchy at speed problem.
If still a ZF pump they are quality units as on my 95 D1 but once they begin to whine they will never become silent again, they are damaged plus worn internally.
Why get someones used rebuilt whining POS, keep your own pump if its silent and have it rebuilt and returned to you. Better yet rebuild it yourself they are basic simple just need to have the proper pulley or hub puller.
Last fall I removed everything and did a slight tightening on the D1 it steered straight before not requiring steering corrections down the highway just a must check anyway thinking being untouched from new back in 95 now at 142K miles. Another weak point LR's rubber hoses, they begin to leak by 5 years use like clockwork......~~=o&o>......

Even at 69K miles I machined custom sector shaft bushings of tighter clearances than