also didnt catch it at first but that 20.5 lb./hr. was @ 43.5psi./3 Bar not sure about equation to convert to my regulator 50 psi idle/ 56-58 psi wot (vacuum unplugged) i would imagine it would be worth checking.
The 'best source for that info' would be a tune file from something that had those injectors installed from the factory. Because injector data is way more than just the flow rate.
Confirmed by the VIN that the truck this file came from used that injector part number (and same regulator type, you still need to confirm with a gauge that your rail pressure is ~58 at key on/engine off): 2000 Sierra 2500 1GTGC24U1YE377854 6.0 4L80E 1299080621.hpt
Open your file. Open the 2000 Sierra file as 'Compare'. Copy these tables from the Sierra into your file: screenshot.02-05-2023 19.22.51.png