[ngoma]

If you've already got the ultrasonic cleaner, and already gotten good results from rebuilding one that had bad spray pattern, why not do the rest?

Clean room practices apply. Do not even handle the nozzle pintles or other surfaces with bare fingers. Always wet with diesel.

Here's one test that can predict final results:
Holding the nozzle body at 45deg. from vertical, partially insert the needle. It should slowly sink to the bottom, of its own weight. Again, wet with diesel.

Do you have a good assortment of shims?

Have you looked at Vince Waldon's VW injector rebuilding tutorial?

Which vendor did you use? So future reader can steer clear.