One of your questions was the diameter of the solder.... my preference is to start with is .015 for the tight work and maybe .031 for the larger components, when you get to cables and wires you might move toward .062.
Just to recap, chisel tip, “lead” solder, heat the component lead and feed the solder to it.
Oddly, I used to have trouble with trembling and gave up stuff like that until I got back into radio. I believe that it was lack of patience causing my issues as now (75yrs) my work actually does (work) and it looks good too !
Glad that I found the 4SQRP, the kits are a blast, hope you have the same experience.
If you need a parachute and don't have one you probably won't need one again.