1. Both
2. The solder only flows where you put the heat, so if the tip is touching (I said tip touching,LOL,)the contact pad and the wire you are soldering that is the only place it can go, I think in the video he used more solder than required to show what a good solder joint should look like, but if you notice the solder still does not flow over to the other contact pad but around it. so on the daughter card as long as you are only making contact with one soldering point at a time you should have no issues. also he doesnât tin the solid wire components this is not necessary, but with a stranded wire it is.