the old 200D nozzles are obsolete parts - they had a pilot hole in them which was used for idling purpose they DN0SD240 - making them whisper nozzles, you can use the later 265 nozzles - they work nice, best to use Monark diesel, 7 diesel, gamma diesel or bosio nozzles in them.
For pump calibration - The haji camp place is useless, trust me I have seen a lot of their idiotic work and they are the main reason of the "bedford raackit" black smoke in Karachi.
Get the pump to cummins Pakistan and ask them to calibrate it properly - they will ask you for your engine no, and also chassis no. as they can then pull the correct litrerature for it.
According to what you say he did the drip time method, that is correct but it is very fiddly as you need a stop watch too to time the drop at 1/sec. with the pump installed, fully primed, delivery nozzle removed and a u bent line installed. You can also do a similar job with a pipe and some air pressure from your mouth. You need to have a clear bottle of water to see the bubbles on discharge.
Remove the tappet cover and set the tappets, Please for the love of God do not try to adjust them with straight spanners as you will break the valve guides, Get two cheap chinese spanners and get a denter to heat them up and bend them to the required shape.
Also tell what is the oil pressure when the engine is hot? and how quick does it start with a normal glow cycle - speaking of which, what glow system are you using - the old series plugs?