It's certainly a good idea to ensure you can start the thread engagement of kingpin bolt by hand but not always as simple as you suggest sewin. With adjustable camber cars (mid 2011 on) for example the domed kingpins locate into a matching concave location underneath top cross arm so their position is pre-determined to a large degree. If the bolt cannot be released by hand then it cannot be restarted by hand with kingpin in same position.
I did find the kingpin bolt can be hand started easily though with everything loose top and bottom providing the adjustable camber bottom plate is loosened to a position which would otherwise leave excessive negative camber i.e. lower kingpin outboard of required. I guess this could be attributed to my particular car but exactly the same was found for both sides. Once everything engaged the correct camber was then wound back in against inner adjustment nut which hadn't changed position, before fully tightening.
