Hanma_Jack
I think that in a year or 2 neji should already have a strong enough chakra and physique to be able to do the kaguya technique, maybe not at the kaguya level of doing the attack without stopping, But he could easily do 5 of those attacks without stopping before he was depleted of chakra. The technique itself does not ask for much, so if you increase your physique and chakra a bit more to the minimum kage level you should be able to use it without much problem, obviously not to its maximum potential.