Lead free solder is inferior, there is not a single lead free formulation that is a good as traditional tin/lead - mechanical properties are usually poorer, as well as being less forgiving of hand soldering technique.
60/40 was the common standard
63/37 is a eutectic, and while the smaller range between liquid and solid may seem better and can be in some situations, it is actually more sensitive to any movement during the setting.
60/40 is solid/liquid at 183/190 C
63/37 is 183 C
99.3 / 0.7Cu is a 227 C eutectic, but prone to tin pest
96.5 / 3.5Ag is a 221 C eutectic, but has poor wetting
Can't find the last one on the list I'm reading.
For fine wires, the best would be a "savbit" type tin/lead/copper - the addition of copper reducing erosion of the soldering bit and of copper wires - but even that, after using standard, you may notice that it's harder to use, less forgiving,