I was only using 60/40 tin-lead or 60/38/2 tin-lead-copper solder back than (no such new age stuff).

Did not see much difference in reliability concerning the solder.

The main problem with such small beasts seems to me getting the solder stick to the machine pin to avoid "cold" connections.

I would try tinning male and female with electronic solder and get it hot enough to join without burning something.

I have some machine pin srings still in my crap box, but age teached me to leave them alone .