When using solder, a 1 mil joint gives the best strength. That's a .001" joint, I believe, or perhaps a bit tighter. This is for high temp silver solder, which requires slightly less heat than welding.

Of course the English doubles are soft soldered, perhaps 50/50, tin to lead. Low temp non-lead solder with 5% silver might to be best to use - don't know that for sure in this application. It's easy flowing charateristics would be nice, though, but one must be very careful not to overhead as with any solder and 'tin' both contacting surfaces properly, of course.