Assembly line technique is what I've always preferred. If you're working with bare switches (unsoldered), do a single specialized task at a time, task by task. This is how I go about my duties:
1) Disassemble every switch. Remove the top housing from the bottom, and separate the spring, stem and housing pieces.
2) Since I don't have a switch plate, I use a propped up G80 PCB for slotting the switch bottoms in preparation. So I put all the switch bottoms into the PCB to keep them in place and easy to work with.
3) Begin lubing every spring and placing them into the switch bottom.
4) Begin lubing every stem and placing them into the spring
5) Snap on the top housing to complete the modified switch.