TD42T injector rebuild

[defender110]

Hi All!
I have a question.
I have removed the injectors from my TD42T (originally from a Nissan Civilian) in order to rebuild them and they have the number 0050T stamped on them.
According to what I saw, the TD42T should have 0050B in them. the actual nozzle number I have is 684 Z (Zexel I suppose) NP-DN0PDN121.
I was looking for a workshop manual that covers the TD42T in order to find the correct numbers, but no luck so far.
To what standard should I have the injectors rebuilt (i.e. cracking pressure?)?
The rebuild will coast me about €280,- (AUD 465,-), will it make sense at all, or should I get new ones?
For the moment I decided not to take off the injector pump in order to check and rebuild it. I want to try the injectors first and see if that will solve my smoking and low power issue.
It seems there is nobody in country (I am in Georgia) who is able to adjust the pump timing correctly. I really would like to get this done, but I am not sure how. What special tools do I need and is it worth getting them for a one off adjustment?
Thanks for your advice!

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