Do it all at once... this way you only have the piece apart once and you can re learn trigger control all at once instead of having to learn it multiple times. Do your springs at the same time. NY trigger kit and springs to bring everything together.
from my studies.... the kits consist of: a 4 or 5lb reduced stiker spring,(lighter springs needs an ultra light weight striker because of light primers hitting) reduced power firing pin safety spring, high polished ffiring pin safety, an extra powered trigger spring, a polished 3.5lb connector and some way to prevent over travel. Delux high dollar kits include a new trigger/bar set up.
On mine, I polish the crap out of everything and install factory 3.5 connectors and use "Super Lube" synthetic grease. This works for me.