I DO know about the need for "unleaded" solder on those sorts of things!
The PIPE Here again...it IS possible to purchase the Wolverine firm's exact 95/5 SnAg solder
in roll form (the "Silvabrite S" formulation) for low-temperature needs, and that firm is located in Warwick, RI, not very far from where I live just south of Boston.
The tin-antimony solder you mentioned IS also a good choice for drinking water systems' soldered joints with copper plumbing - at least both SnAg and SnSb (Sb is antimony's periodic table abbreviation) kinds of solder HAVE NO LEAD in them, making them ideal choices for "unleaded" solder for such needs.
My homebuilt RC hobby electronics PC board and wiring soldering needs
WILL continue to be done with the older, 63/37 "eutectic" tin-lead solder, though...I haven't done that in a while now, but when it's time to get back to the RC hobby once again, and time to build more MicroStar-based knobby radios for my own needs as one example, 63/37 SnPb regular "leaded" solder will always be my best choice for those.