I believe I owe an apology or two if I came off as curt.

New nozzles, correctly rebuilt injectors will sound "different" The loud chatter will go away roughly by 200-500 miles on any rebuild. That is normal. However, there are no misses either at start up or when cold. They are the same hot or cold. Now, if you experience a metal like or metalic like clang, that is air. It will work itself out within 50 or so miles. If it does not, then you have an air leak somewhere.

As for the IP timing, I have an AVL 875 BUND device. It says 20*, but that is really 26* since you add 6* when I time my engine. I know adjusting the valves will cause the injectors to simmer down a hair. Not sure why, but it does. I am happy with 26*.

I will be experimenting with speciality ground pintles which push a huge amount of fuel, so I can report back the effects of more fuel, e.g., timing, engine idle, et cet.

However, generally, well balanced injectors (those within +/- 25PSI) should produce a really fine idle once they settle in. I know that from experience since FSM is 50+/- PSI and most "pro" shops hit around +/-75PSI and there is a huge difference in smoothness with the balance issue.