My method was to lightly file the pins with a jewler's file to get ALL tarnish removed.
Then you carefully and
quickly "tin" those pins with a thin application of solder. Remember that you're working near plastic so be quick about it. I recommend a quality precision iron, not something used for sheetmetal work.
Then you tin the ends of your pigtails, with about 1/4 inch of insulation removed. Try to leave a little blob of solder on the wire. Not a big blob, just a generous coating. This will be the solder that holds the two together.
Then you hold that tinned wire against the pin and
quickly melt the solder on both items, focusing on that little blob. When that melts, you're done.
If you're not a skilled solder guy, you could take your prepared components to a geek/repair place and have them do it in 15 minutes. I highly recommend you label your pigtails with the color code. It can be REALLY confusing when looking at the FSM diagram vs. the real thing, because the view in the FSM is backwards or mirror image or something. Maybe it's the back of the switch that's depicted, NOT the front of the OEM connector. Or the opposite...I forget. Anyway....it's not intuitive when looking at the diagram so be careful. The good news is, if you screw it up and the wrong window moves the wrong way, you can move the bullet connectors around until you get it right.
Here's a pic of the pigtail version vs. the OEM connector (that I laid out with the crappy terminals in their proper places.
View attachment 247791
View attachment 247790