I need to pull some doubled up , 0.22mm (9 mil, SWG 34, AWG 32) Cu wire
through small bore sleeving. Some 0.3mm nichrome heater element wire
stretched out until straight, worked rigidly enough, with "peristaltic"
movement as a mouse (does this term translate across the pond ?) . I was
probably lucky that "soldering" the copper to the ni-chrome made a
sufficient strength overlap join to pull 1 wire through but I doubt it would
work pulling 2 through, soldered or glued, because of added thickness of
overlap bulge, when I have to repeat the process for the double one.

Can anyone think of a source for thin wall ferrule / coupler to solder or
probably glue over a butt join between mouse and 2 Cu wires, of these sorts
of dimensions.
Butchered mini-din socket pins are a bit too big diameter, but anything like
that ?