Lockshields not very effective?

[JamesAsus]

Trying to balance my system as all the upstairs rads get boiling instantly and my downstairs rad takes a good 30 mins to get fully warm.

Issue im having tho, is even the tiniest turn of the lockshield seems to take the radiator from fully closed to fully open, i cant open it slightly to slow down the flow into ANY of the other radiators, they are all the same, radiators about 28 year old, not sure any of the lockshields have ever been replaced but i doubt it.

 

[Madrab]

Not a lot you can do then if the lockshields are that bad. That being said, lockshields are sensitive by their very nature and something as small as an 1/8th of a turn can be as much of an adjustment that it needs